The space optical backbone network is the core of China’s spacial information network. In order to verify the feasibility of the network protocol, the network architecture and the key technologies in the space optical backbone network, a space optical backbone network simulation platform based on OPNET and satellite tool kit( STK) was designed.A space-based backbone network consisting of 4 geostationary earth orbit (GEO) satellites and a space-based access network consisting of 10 low earth orbit (LEO) satellites were designed.And the optical network protocol simulation model from the physical layer to the application layer and the 3 node process models of LEO, GEO and ground stations were developed, moreover, the optical backbone network was simulated and tested. The simulation results show that the maximum delay of the space optical backbone network is 5.48 s, the minimum is 0.35 s, and the global average network delay is 1.06 s. The maximum real-time throughput of the ground station is 0.88 Gbps with a minimum of 0.3 Gbps. The research results indicate that the platform can accurately simulate the function of spatial optical backbone network, meet the needs of efficient transmission of space services, and provide simulation platform support for spatial optical backbone network performance verification.