Aiming at the problem of dynamic time-varying network topology and diversified service types in satellite optical network, the routing technology was studied to guarantee quality of service (QoS) under the framework of software-defined network (SDN), and a multi-service based ant colony optimization wavelength routing algorithm for satellite optical network was proposed. The heuristic function of ant colony algorithm was improved. The wavelength idle rate, time delay, time delay jitter and packet loss rate were taken as the important basis of ant routing, and the optimal path satisfying various QoS was selected for business. The group wavelength assignment strategy (GWAS) was used to distinguish services of different levels. Different sets of wavelengths were assigned to different services. The simulation results show that compared with CL-ACRWA algorithm and Dijkstra algorithm, the average delay, average delay jitter and average packet loss rate of satellite optical network are reduced. The wavelength utilization is improved. The network congestion probability of high-priority services is reduced.