Acquisition, pointing and tracking (APT) system is an important part in space laser communication, which is the premise and guarantee for normal work. The composition principle of system, operational principle, key technology, system design and engineering implementation are researched in detail. The simulation experiment indoor and dynamic experiment outdoor are carried out, respectively. The tracking precision in simulation experiment is 2~3 μrad, which proves this system can be used in inter-satellite laser communication. Dynamic demonstration experiment is achieved between airship and ship. The results prove that the acquisition probability is higher than 95%, and acquisition time is less than 60 s. Because of turbulence effect, tracking precision will decrease observably. The tracking precision in turbulence is 5~25 μrad, Development of APT system establishs the foundation for space laser communication execution successfully.