Abstract: Based on Monte-Carlo simulation, the achievable information rate of the Q-ary pulse-position modulation and avalanche photodiode (APD)-based deep-space optical uplink channel was investigated for the beam wander and intensity fluctuation model. The results indicate that unlike the downlink channel, when the beam wander effect is taken into account, optimum divergence angle can be selected to achieve the maximum achievable information rate for the uplink channel. Besides, with respect to achievable information rate, the optimum divergence angle dependence on the transmitted beam number, the zenith angle, thermal noise and transmitted beam width have been evaluated. This work can be helpful for the uplink laser communication system design.