Abstract: A parameters estimation algorithm based on the power spectral FFT is proposed to estimate the parameters of Binary Phase Shift Keying (BPSK) signals under negative Signal-to-Noise Ratio (SNR) environment. The code width, carrier frequency and code length of BPSK signals are estimated according to the relationship between the parameters and the amplitude and phase spectrums, which are obtained through the FFT of power spectrum. This algorithm can further eliminate the noise based on power spectral FFT, so it is more suitable for low SNR environment. And the algorithm is computationally efficient and easy to realize. The experimental results demonstrate high accuracy and stronger capability on anti-noise, the estimation of the carrier frequency and the code width can increase by 9.9% and 190.9% with the cyclic spectral estimation algorithms.