An automatic tracking measurement system was designed to achieve real-time measurement for motion parameters of long-range air targets, such as aircraft. Hardware, software and key technologies were described in this system. The prototype was made and tested, the software structure design and corresponding functional modules were analyzed. Multiple experiments are presented to testify the working performance of the system. The static verification experiment indicates that the ranging results are stable within 1mm and the azimuth measurement results are stable within 5″. And the dynamic verification experiment indicates that the ranging error of moving target is 2 mm, the ranging frequency is 5Hz, the azimuth measurement error is 0.05°, and the posture measurement error is maintained at a level less than 0.2°, the real time measurement frequency of azimuth and posture are 20Hz. From the above analysis, the system can provide a stable, reliable and high precision automatic real-time measurement when testing motion parameters of aerial target.