The design on orthogonal waveform is the precondition of waveform diversity ability on MIMO radar, the performance of waveform diversity ability on MIMO radar is influenced by the Auto-correlation Peak Side lobes. the format of MIMO radar, selection of optimized algorithm and the result of waveform design are analyzed in this paper. Finally, the traditional polyphase-coded and the genetic algorithm are simulated and compared with the orthogonal waveform design.