The emitted laser is a single frequency source in the traditional coherent detection, and this system can be used in the field of objects measuring and tracking. But in the typical ladar system abroad, it can be used in Range-Doppler(R-D) imaging through the mode-locked pulse burst combined with coherent receiving method. Therefore, the numerical simulation of R-D imaging based on the mode-locked laser pulse burst was analyzed. Firstly, the numerical model of the mode-locked pulse burst was built up. Secondly, the unfolded frequency spectral of the laser pulse was given and the matched filter of the echo signal was designed through the spinned-target model. At last, the FFT and IFFT were adopted in the processing while the R-D image can be obtained with different rotating angular speed. On the other hand, the SNR can be enhanced with many frame accumulations based on the R-D image output. From the simulation analysis of R-D imaging, the fingerprint image of the spinned-target with a macro-pulse(including many micro pulses) was obtained, it is very important in the target discrimination of the ballistic missile defense.