The invention discloses a fragmentation transcoding method and system of the live video and the real-time video. The method comprises the following steps: when a live program is performed for p seconds, the p seconds of program video is transcoded and then transmitted to the client side; when the live program is performed for p+a*p seconds, the video from the (p+(a-1)*p/k)-th second to the (p+a*p/k)-th second is transcoded according to the transcoding speed and transmission speed of the program video, wherein a is a natural number; after each fragment completes transcoding, the fragments are transmitted to the client side, wherein the transcoding speed of the program video is g, the transmission speed of the program video is h, the transcoding time of the first p seconds of the program video is m seconds, the time that the first p seconds of the program video is transmitted to the client side after transcoding is n seconds, g=p/m, h=p/n; the transcoding time of the first p/k seconds is about (p/k)/g seconds, the time that the first p/k seconds of video is transmitted to the client side after transcoding is (p/k)/h; and k satisfied the following condition: p+m+n>p/k+(p/k)/g+(p/k)/h. By using the method of the invention, the times of the first fragment and the other fragments can be well determined, and the program video broadcasting on the client side can not be interrupted.