A dualdetector compoundaxis APT scheme of airborne laser communication is proposed, according to the environment of communication link. The compound axis consists of Coarse Tracking Assembly (CTA) and Fine Tracking Assembly (FTA). A detailed analysis and optimization design of whole optical path structure is carried out. Then a technique about switching between coarse beacon and fine beacon is put forward. This way improves energy density of fine beacon and therefore can make CCD high frame work. Finally, it improves servo bandwidth of FTA. CTA performances a wide range of pointing and tracking, with tracking accuracy of up to 120 μrad. However, servo bandwidth of FTA is greater than 300 Hz, with dynamic range of 5 mrad and tracking accuracy of 3 μrad. The planetoground laser communication demonstration experiment is successfully completed, with the distance of 17.5 km, the communication rate of 1.5 Gbps, and BER of less than 1E7.