A method for guaranteeing service reliability in an end-to-end Quality of Service framework, including: checking whether connection information held in all node equipment gone through by a session connection is consistent; if it is, finishing the consistency check; otherwise, releasing the inconsistent connection information from the node equipment. In this invention, consistency check is performed inside every node equipment, and between node equipment in the network, and thus, abnormal resources may be retrieved, so that network service ability will not be affected by abnormal situations. When the network is of large scope, consistency check can be done according to signaling flow sequence for establishing a session connection. When an inconsistent situation is detected, the node equipment gives a feedback to its upstream node equipment. Usually, there is a great quantity of sessions on a network, so it is better to carry out consistency check in batch for decreasing spending. With this method, degradation of service ability because of network abnormity can be avoided, and network reliability and availability can be improved, which is of great economic benefits.