Abstract: The orthogonal performance of between signals is crucial for implementing multiple inputmultiple output (MIMO) radar system. Orthogonal discrete frequency coding waveform (DFCW) can be utilized toMIMO radar. This paper firstly analyses the ambiguity of DFCW and investigates the autocorrelation sidelobe peak(ASP) and cross-correlation peak (CP) level. The genetic algorithm is also proposed to optimize DFCW with lowercross-correlation peak. Then the designed DFCW is utilized to MIMO radar and its matched filter performance isanalyzed. Simulation results validate the investigation of cross-ambiguity and the analysis.