To improve the tracking accuracy of free-space satellite quantum laser communication ground terminals and achieve a lightweight design, a lightweight quantum laser communication tracking system based on dual-detector compound-axis tracking technology is designed. The system adopts a T-shaped aluminum alloy tracking frame and a silicon carbide primary mirror structure, combined with a coarse-fine tracking hierarchical control strategy. Residual errors are compensated by a piezoelectric fast steering mirror, and an intelligent parameter-tuning proportional-integral-derivative（PID）control algorithm is introduced to optimize parameters. Experimental results show that during the satellite-to-ground field test, the standard deviation of coarse tracking accuracy is 4 arcsec（azimuth axis）and 6.3 arcsec（elevation axis）. After fine tracking closed-loop correction, the composite error standard deviation is reduced to 1.4 arcsec（azimuth axis）and 1.2 arcsec（elevation axis）. Meanwhile, the system weight is reduced by 50% compared with traditional designs.