Abstract: The effect of the initial velocity increment场escape energy on the time-optimal rendezvous problem by solar sailing is discussed. The effect of escape energy is considered as the inequality constraints on the functions of the state variables specified at the initial time, and an indirect method is used to obtain the two-point-boundary-value-problem(TPBVP) associated to the optimal control model. The results indicate that the optimal control model can be used for calculating the best escape energy usage，and the optimal trajectory is not always obtained by using the largest escape energy. Thus , a rational utilization of escape energy can shorten the transfer flight time. The model in this paper can effectively utilize the late stage rocket booster ability; and effectively shorten the solar sailing mission time as well.Therefore, it is practical and valuable for engineering application.