Abstract: With strictly orthogonal Walsh matrix, genetic algorithm optimize in the polyphase code orthogonal space that is generated by the matrix structure and random column rearrangement. This method ensures the strict orthogonality and reduces the search space of the genetic alogorithm. The cost function contains autocorrelation peaks sidelobe, crosscorrelation peaks and sumsignal(all channel signals superposition) correlation peaks sidelobe. The sumsignal correlation output is the integrated output of actual signal processing, and its sidelobe directly affect the performance of the radar target detection. The simulation results demonstrate that the method can design the strictly orthogonal and low integrated output sidelobe signal with the low contains autocorrelation peaks sidelobe and crosscorrelation peaks.