Abstract: Investigates an improved motion vector based Mpeg 2 video digital watermark technique. Through analysis of the Mpeg 2 standard, combined Jordan's algorithm which embeds digital watermark in motion vector and human eye system, watermark is located in a suitable block of inter frame according to the value of the motion vector and the character of image texture. The experimental result indicates that this method can hide the watermark in the Mpeg 2 compressed stream more rationally. The average peak SNR is improved 12%～21% than in the original algorithm, and reduces the error rate.