Abstract: In the virtualized environment, the multi-layer complexity of the network and the inaccuracy of information lead to the low accuracy of the virtual network service fault diagnosis algorithm. In order to solve this problem, based on the characteristics and associations of services, virtual network resources and substrate network resources, a fault diagnosis algorithm for virtual network services based on resource characteristics is proposed. According to the service bearer and resource mapping relationship, a set of suspected virtual faults was constructed. According to the number of symptoms, the number of virtual nodes, the probability model of negative symptoms and substrate nodes, the reliability of faulty nodes was analyzed and a fault propagation model was dynamically constructed. The virtual network service fault was located by analyzing the ability of the suspected fault set to explain the negative symptoms. From the two aspects of simple network environment and complex network environment, it is verified that this algorithm can improve the accuracy of fault diagnosis, and reduce the false alarm rate and diagnosis time of fault diagnosis.