A method and apparatus is disclosed for calculating a Doppler signal spectrum. The method includes a step of estimating parameters of a Doppler signal, and a step of resolving a predefined spectrum function using the parameters, the spectrum function being at least a function of the parameters characterizing the strength, frequency center, and frequency deviation of the Doppler signal. The apparatus includes an estimating module, a smoothing module, and a calculating module. According to the Doppler signal spectrum calculating method and apparatus of the present disclosure, the obtained spectrogram has very high time and frequency resolution without requiring any complicated operation. Thus, a higher quality spectrogram can be obtained at a very low cost.