The invention discloses a gesture function input method and system. The method comprises the steps of S110, obtaining a current gesture action image of a user in a preset time period; S120, identifying gesture key point coordinates of each frame in the current gesture action image, and calculating a gesture freedom parameter of each frame; S130, according to the gesture freedom parameter of each frame, determining preset parameter similarity of all frames; S140, comparing the preset parameter similarity with a preset similarity threshold, and when the preset parameter similarity meets the preset similarity threshold and is different from a pre-stored gesture function, determining the current gesture action image as a target gesture action image, otherwise, repeatedly executing the steps S110-S140; and S150, obtaining an operation instruction corresponding to the target gesture action image and used for input, thereby finishing gesture function input. The method is simple, provides a solution way for users to define gesture interaction systems, and can enable different users to realize personalized gesture interaction systems for their demands.