In order to tackle the issue of high integration and mutual feedback enhancement of the resources of multi-satellite and inter-satellite communication and computing systems, an integrated satellite routing algorithm OISL-DDPG is proposed based on optical inter-satellite link-optical service unit（OISL-OSU）. OISL-DDPG adopts the deep deterministic policy gradient （DDPG） optimization method to enhance the quality of service（QoS） performance of satellite optical networks. The simulation experiments indicat that the network slicing method based on time windows is consistent with the actual network operation status of domestic low-orbit constellations. Additionally, the proposed algorithm achieves higher link utilization and link occupancy rates at the cost of increasing slight delay than the minimum hop algorithm, and gets a better convergence rate, lower latency, and lower packet loss rate than the multi-constrained shortest path first（MCSPF） algorithm.