Power coupling efficiency of beam uplink propagation is a critical factor of the relay mirror system. By optimizing the optical phase at the launching telescope, the intensity distribution at the receiving telescope can be shaped and power coupling efficiency of the two-telescope system can be improved. Model of the two-telescope system is established, results of the 0.1～0.5 m two-telescope system with 10 km and 30 km propagation distance are calculated. The results show that the power coupling efficiency can be significantly improved.