Abstract: Non linear editing systems based on MPEG 1/2 tend to replace M JPEG based non linear editing systems. As a result of the structure of the stream, the audio stream editing is very difficult to adapt to the video stream synchronically. A kind of synchronism editing algorithm is provided. Based on an analysis of the construction of the MPEG 1/2 stream, and making use of the PTS parameters of the video, a synchronism editing algorithm is realized. Characters of the algorithm are effective, and there is no audio quality loss because it needs not to code or decode any audio frame, and so it is a fast algorithm. Editing for a limited number of times is even better because of the accumulation of the editing error.