Character animation which is used to show human figure has been extensively applied in VR (Visual Reality) field. Because too much initial work is being repeated, it usually costs more than needed to make character animation, and the technical difficulty is also at a high level. Large game corporations incline to keep the core technologies of character animation as commercial secrets, thus block its development. In this paper, the main framework of a “3D character animation engine” is designed. Great emphasis is put on the principle of different types of character animation and their realization methods. The 3D character animation engine provides consistent APIs for key-frame animation, mixed animation and morph animation. It enable users make character animation through programming in a fast and easy way.