Abstract: This paper is focusing on the MPSK signal’s symbol rate estimation problem under wideband receiving situation. As the wideband data comprises lots of separated narrowband signals, channelization using analysis filterbanks is needed. When the carrier frequency is unknown and have random distribution, the MPSK signal may be divided into several subband signals. This paper is aimed to discuss the symbolrate estimation problem using the spectrumdistorted subband signal. The model of MPSK subband signal is proposed firstly. The spectrum distortion can be considered as the transition of shape function after theoretical analysis. Then a new symbol rate estimation method is presented based on the complex envelope of the subband signal. The estimation is unbiased which is proven by the deduction of the estimation expectation. The influence of the frequency domain coverage percentage and SNR are analyzed with the computer simulation at last. When 30% of the signal spectrum is damaged, the SNR should be 4dB higher in order to achieve the same estimation accuracy under no spectrum damage circumstance. Under the CCIRModerate HF channel environment, the SNR should be approximately 3dB higher to achieve the same performance under Additive White Gauss Noise (AWGN) circumstance. The efficiency and credibility of the method are testified by the theoretical deduction and simulations.