A method of developing cartoon game on traffic safety education of Chinese children is presented in this paper. Based on the psychological characteristic of children and constructivism learning theory, the design of game scenario, character’s emotion and interaction is introduced. The scene in this cartoon game is based on Gibson’s theory of affordances and all the signs on objects are easily distinguished. A finite state machine is used for expressing the emotion state of a cartoon character, and NPC (non player character) is introduced to arouse the interest of a child user. The cartoon game can run both on local PC and on Internet, a child user can learn safety knowledge by interactive method. The result will offer a new means for traffic safety education of children in china.