Abstract: The signal fusion of multiple frequency bands and multiple radars is an effective method to improve the range profile resolution. Coherent processing is an important step before multiband fusion. This paper analyzes the uncoherence between the moving target’s frequency responses from different radars. Usually traditional coherent methods need to extrapolate the spectra of subbands， which causes depravation of coherent precision in low signal-to-noise and brings heavy computer load. So the authors present a coherent method using the poles’ information directly without extrapolating the spectra. Also the processing flow and several problems which we will encounter are particularly analyzed. The validity of the presented method is proved through computer simulation and real world data experiment.