To meet the requirements of satellite laser switching network, such as fine robustness and high physical realizability, emulated-optical burst switching (OBS) is selected as the architecture of relay satellite, and an on-board resource reservation protocol, whose offset time is constant, is proposed combining the ground resource reservation methods. Traffic prediction is used to differentiate the data burst into single burst or burst stream according to the destination and quality of service (QoS), then resource reservation is accomplished successfully. To validate it, mathematic models of mean end-end delay, throughput, link utility and burst loss probability are established. The results of analysis and emulation show that the protocol can reduce the reconfiguration time and switching time of optical switch matrix through burst stream scheme, and decrease the complexity and cache size requirement through the E-OBS architecture, so the new resource reservation protocol meets the requirements of satellite laser communication.