The disclosure provides a method and system for encoding bit rate control and version selection for a dynamic adaptive video streaming media. The method adopts a dynamic adaptive streaming media encoding technology to encode each original video into a plurality of versions with different bit rates at a server and determines video version subsets to be encoded by the original videos and specific encoding parameters of each video version by taking an encoding complexity-bit rate-distortion model for different original video contents, constraints on an encoding bit rate and a computing resource of the video server, network connection conditions of different users and a video-on-demand probability distribution into consideration, and finally, the video server outputs an optimal video version set through encoding, so as to maximize the overall quality of videos watched by users.