Abstract: Based on studying the generating principle of TDDM-BOC(time division data modulation-binary offset carrier) modulation signal,the characteristics of TDDM-BOC modulation signal are analyzed.According to the relationship between auto-correlation function and parameters of signal,a method is proposed to estimate the parameters of the TDDM-BOC signal.The frequencies of the carrier wave,spread-spectrum code and square subcarrier are estimated effectively,and the method performance is simulated.The simulation results show that the method can work well at SNR > -14 dB.