Abstract: In order to obtain more characteristics of target signal and improve identification probability, method of short Fourier transform is introduced to analyze the signal in time and frequency domain. The choice method of window function is given combined with the millimeter wave (MMW) signal feature of frequency chart of the target tank. Difference of MMW signal feature of frequency chart between the target and its main interference is analyzed. Based on this, the choosing method of MMW signal feature in time-frequency domain is given. Analysis result showed that the MMW signal feature in frequency domain of tank using the analysis method in time and frequency domain based on short Fourier transform is greatly different from its main interferes so as to identify the tank target.