This paper deals with the interoperability errors in the process of Web services. The communication data are first captured and then stored in the ontology library. The analysis is done in light of the JESS reasoning system on the basis of the analysis rules. The testing system is flexible, for it can distinguish new error types by adding the corresponding rules into the ontology library. To identify more errors, a simulation of network communication failure is conducted on the basis of the control rules. The elements of Petri-net are mapped to the ontology library to replay the operation process to help users gain a better understanding of it.