Abstract: A new algorithm for estimating the parameters of LFMCW signals is presented.The Time-Frequency curve can be obtained by short-time Fourier transform.According to the periodic characters of the Time-Frequency curve,the characters of the frequency spectrum of the curve can be found.The relationship between parameters of signals and spectrum-lines' positions or amplitudes can be confirmed.Then the main parameters of signal can be obtained.Simulation results prove that the method can estimate the parameters of LFMCW signals accurately.When the signal-noise ratio is higher than-8 dB,the performance of the algorithm is stable and the precision of the algorithm is good.