"''Xiao Xiao''" literally is the Chinese character for "small" repeated twice in ; here this reduplication connotes an affectionate diminutive – an equivalent might be the English expression "itty bitty" or "lil' old". Each Xiao Xiao cartoon is given a Chinese title with the adjective "Xiao Xiao" preceding a descriptive noun phrase. Xiao Xiao #1 was originally titled "Xiao Xiao Zuo Pin", which translates to "A Little Bit of Creative Work". Since then each Xiao Xiao cartoon has had a different noun succeeding "Xiao Xiao" – #4 is titled "Little Sheriff", and #7 is titled "Little Movie".
The term has gradually shifted meaning from the cartoons themselves to the main character, an anonymous black stick-figure – in this context it means something akin to "little fella", appropriate since in most perspectives Xiao Xiao and his fellow stick-people appear tiny and childlike, with disproportionately large heads and small limbs.
Xiao Xiao is placed in various dangerous situations to prove his martial arts prowess, often against other stick figures who appear more or less identical to himself. Usually other stick figures are also black, but can be other colors, and Xiao Xiao's perpetual nemesis is the Boss, a purple stick figure who commands the enemy sticks and appears to be Xiao Xiao's only peer in ability.
Others have seized on Xiao Xiao's popularity to make animations exploiting the easy-to-draw style of stick figures and minimalist backgrounds, often creating cartoons that are sequels or takeoffs of the official Xiao Xiao cartoons, especially Xiao Xiao #3. This practice has been frowned upon by many in the Flash cartooning community.
* Xiao Xiao #1 is a simple fight between two stick-figure men, parodying the look of Hong Kong martial arts films by taking the level of violence in the fight to extremes.
* Xiao Xiao #2 adds interactivity; the stick-man faces a series of physical challenges, the outcomes of which depend on the player's timing.
* Xiao Xiao #3 is a kung-fu style fight scene in a simple line-drawn house; Xiao Xiao faces off against a seemingly endless series of stick-man opponents using fast-paced martial arts moves; the simple background, two-dimensional movement, vanishing corpses and regenerating enemies call to mind side-scrolling games. The encounter ends in a final showdown between Xiao Xiao and a purple stick-man labeled "Boss" in a fight that parodies multiple scenes from The Matrix . The visual theme of Xiao Xiao, a plain black stick-man, fighting against a purple stick-man Boss, remains constant throughout the series. This is the best known Xiao Xiao animation, and has been shown on MTV. This Xiao Xiao is one of the more famous and thought of as the one hardest worked on, and is noted to be one of "the original stick fighting flash movies", and sets the bar for the many stick flash movies.
* Xiao Xiao #4 is an interactive first-person shooting game in the style of Virtua Cop, casting the player as Xiao Xiao in the role of a -style sheriff complete with cowboy hat and six-shooter. It ends with another scripted fight scene with the purple Boss .
* Xiao Xiao #5, billed as a "''Battle to the death... and beyond''" returns to the two-dimensional fighting-game-reminiscent side-view style of #3. This time Xiao Xiao and the Boss duel using various conventions from anime and manga, exhibiting supernatural powers such as the use of spells, the ability to pull weapons out of hammerspace and to continue their battle through astral travel after death. It is notable for its comedic ending, where an ambulance shows up in the middle of the fight, taking the two character's dead bodies away. The two look at one another, then both run after the ambulance.
* Xiao Xiao #6 returns to Xiao Xiao #2's style but this time with a bit more of a plot, forcing the player to button-mash Xiao-Xiao through a barroom brawl.
* Xiao Xiao #7 and #8 are the most elaborate of the animations, forsaking the side-view of previous Xiao Xiaos for a fully three-dimensional, cinematic camera view throughout. Once again riffing on films like ''The Matrix'', they depict Xiao Xiao's infiltration of the Boss's mansion and his pursuit after the Boss escapes. #8 ends with a "''To Be Continued''" message and has yet to have a sequel, though given that the ending is a bit of an anticlimax the message may have been ironic.
* Xiao Xiao #9, a departure from the rest of the series, is a fully interactive game in the style of Final Fight and Streets of Rage where Xiao Xiao uses moves. Rather than a plain, pen-and-ink background, the background is this time a full-color, realistic re-creation of a desk ostensibly intended to be Zhu's . As with other Xiao Xiaos and the original beat-em-ups that helped inspire them, Xiao Xiao must fight through a series of stick-thugs before confronting the Boss.
* Xiao Xiao #10 or Xiao Xiao: Mall Brawl appears to have been created by Zhu as an advertisement for the in Hong Kong; it is an altered version of Xiao Xiao #3 wherein the main character/hero is a red stickman and the background has been embellished to make it resemble the inside of a shopping mall. You can also see the original black Xiao Xiao making a cameo appearance for a short while. He is in the background and doesn't fight, but simply rides past on a pair of ice skates. Also, a scene from Xiao Xiao #3 is also playing on the TV during the fight.
*;Xiao Xiao: Xiao Xiao is the protagonist. He is a martial arts expert, as well as an elite assassin. His skills are unmatched, and the only person who comes close is the Boss.
*;The Boss: The Boss is another martial artist, and appears to be some sort of a gang leader. He is the only one who can give Xiao Xiao a decent fight, and has been beaten by Xiao Xiao on multiple occasions. The Boss usually appears in magenta.
*;The gangs: Various-colored stickfigures who are beat down by Xiao in a matter of seconds.
In June 2004, Zhu filed a lawsuit against for plagiarizing his cartoon stickmen in their commercials. Nike representatives denied the accusations, claiming that the stickman figure lacks originality, and is public domain. Zhu eventually won the lawsuit, and Nike was ordered to pay $36,000 to the cartoonist. However, on June 15 2006, the Beijing High People’s Court overturned the lower court's verdict. The high court rejected the December ’04 ruling that found Nike had “copied his ‘Little Match Man’ illustration in one of its worldwide ad campaigns.” Judge Liu Hui ruled that the head of Nike’s “stickman wasn’t attached to the body, which was different from Zhu’s design and that the strokes used to draw the Nike figure’s arms and legs were different from Zhu’s also.” Zhu will now have to pay court fees of more than US $5,000 to Nike.