A real-time data acquisition inverse synthetic aperture ladar system is designed. The continuous m-sequence phase modulation method is employed to image a rotating target at a distance of 33.5 m by a 1550 nm laser with the average power of 2 W. The range-Doppler domain imaging result reveals the characteristic of the target, distinctly. In the imaging demonstration, the range resolution and the cross-range resolution are 18 cm and 1.576 kHz, respectively.