The link transmission performance of the unmanned aerial vehicle (UAV) retro-modulating optical communication system under the weak turbulence condition is studied and verified by simulation. The influence of pointing error on the system is considered, and the Gauss-Hermite integral method is used to derive the bidirectional channel fading probability density function and the closed expression of its cumulative distribution function for this system. The closed expressions of system average bit error rate and the outage probability are further derived. The research results show that under the joint influences of weak turbulence and pointing error, and the incident angle, modulation order and refractive index of the corner cube retro-reflector have great influences on the error performance of this system. When the divergence angle is 3-10 μrad, the system error rate reaches an optimal value. When the divergence angles are 6, 8 and 10 μrad, respectively, the outage probability is reduced to 10 -9 orders of magnitude under the condition of relatively high signal-to-noise ratio threshold.