On the basis of the development status of total mixed ration mixer in China, the paddle-wheel total mixed ration mixer was developed. To reveal mixing principle of the mixer, the mixing chamber was divided into four districts, and research of the mixing process was conducted by using high-speed cameras (1200 frames/s, 4G). This study showed that shear mixing, convective mixing and diffusion mixing were the main modes in the mixing process, and accompanied by gliding motion, waterfall movement and eddy motion. It could be obtained that the rotor speed, angle of the mixing paddle, mixing time and fullness coefficient had greater influences on the mixing performance of the paddle-wheel total mixed ration mixer. Then, the above four parameters were decided as experimental factors, and variation coefficient was chosen as the evaluation index, experiments were done by design method of quadratic regression orthogonal rotational combination. Through the experimental study on paddle-wheel total mixed ration mixer, the main parameters in structure and motion of the mixer were optimized and determined as follows: rotor speed of 29~31r/min, the angle of mixing paddle of 16°~26°, mixing time of 10~12min, fullness coefficient of 48%~53%. The research of paddle-wheel total mixed ration mixer could provide a theoretical support for the optimum design and performance forecast of the mixer.