this thesis introduces a method of MPEG-4 video encoder based on embedded ARM CPU. This method realizes MPEG-4 video coding subset, which is based on embedded Linux and MXL hardware. In order to improve coding efficiency, the thesis optimizes encoder from aspects of algorithm and structure and so on. Firstly, it uses the hardware of embedded multimedia processors to achieve DCT algorithm. And it has a optimization for a key of motion estimation, uantization, a half-pixel interpolation and so on, then In this paper, a half-pixel search algorithm, which is based on motion estimation, is proposed. And a half-pixel search algorithm is optimized. The standard test sequence experiment shows that it is feasible.