The invention discloses a deep-space network routing method with a QoS (Quality of Service) assurance, and solves the problem in the prior art that deep-space network service requirements can not be satisfied. The method particularly comprises the following steps: acquiring all link information in the network at first, correcting the communication time slots, then bringing link transmission time delay and link transmission rate into consideration to calculate the transmission time slots, and finally, calculating the path time delay according to the path transmission time to select the minimal path as the optimal path. By adopting the method, the calculated and acquired path time delay is more accurate, the selected optimal path has the shortest time delay, and the QoS requirement for the time delay of the service can be satisfied while the service throughput is guaranteed; and the service transmission time can be set more reasonably, the data transmission blindness is small, the probability of false transmission due to disconnection of links when data is transmitted on the links is low, and the network performance is improved.