ing at the problem that the inter-satellite laser communication system is easily affected by the pointing errors, the method of third-order central moment is used to make the pointing error equivalent to the modified Rayleigh distribution under the condition that the pointing errors obey the Beckmann distribution. Under the assumptions that the outage probability and the transmission power are fixed, the optimal model of transmitter power and the optimal model of outage probability are established, respectively. The optimal root mean square width of the Gaussian beam emitted by the antenna under the above two assumptions is calculated. Through the numerical simulation, the numerical relationship of the outage probability and the minimum transmitting power with the optimal root mean square width is given. According to the numerical analysis results, the optimal root mean square width of a Gaussian beam can be selected based on the definite pointing error distributions, so that the optimal link performance for the inter-satellite laser communications is obtained.