The invention discloses a dynamic adaptive code rate selection method based on a MPEG-DASH (MPEG-Dynamic Adaptive Streaming over HTTP) protocol. The dynamic adaptive code rate selection method comprises the steps of: firstly, establishing a HTTP connection between a server and a client; by the client, sending a HTTP Get request to the server, requesting to download a MPD file and storing the MPD file; after the server receives the request of the client, by the server, responding to the client and sending the MPD file, and by the client, downloading the MPD file and parsing the downloaded MPD file; according to an URL address obtained by parsing the MPD file, firstly downloading one part of a slice at the minimum code rate, placing the slice into a cache region, carrying out calculation, statistics and recording on a network bandwidth when the video slice is downloaded, and predicting a network bandwidth when a next video slice is downloaded; and by combining a current residue condition of video slices of the cache region, selecting a code rate for downloading the next video slice until the end. An effect of improving video quality to the greatest extent in the premise of smoothly carrying out playing is achieved, and viewing experience of a user is greatly enhanced.