Abstract: Radar waveform design is becoming a research focus in the field of radar．First，this paper puts forward a kind of OFDM(Orthogonal Frequency Division Multiplexing)chaotic random phase coded signal，on the basis of this signal，using a chaotic sequence to modulate the frequency of each sub-carrier in OFDM and produce a kind of OFDM radar signal form with random phase and frequency，then analysis this radar signal ambiguity function、auto-correlation and the influence of its sub-carrier number．Analysis the problems of this chaotic coded signal and study the method how to reduce its PMEPR(Peak to Mean Envelope Power Ratio)．Simulation results show that the phase and frequency joint modulation OFDM coded signal has the better ambiguity function and auto-correlation side-lobe．Due to the complexity and randomness of chaotic sequences，the signal has the better low probability interception．