Abstract: The interlock safety logic was reflected by interlock table. This paper proposed a verification method based on CSP (Communicating Sequential Processes) to solve the data safety logic verification problem of interlock table, modeled data of the interlock table at first, abstracted five processes of dispatchers, switch, signal machine, segment and interlocking controller from the data of interlocking table, and further modeled the processes respectively. The correctness of the model was verified from the functional and safety aspects. At last, an example of data safety logic verification with the interlock table in Yi Zhuang Station of Beijing Metro illustrated the feasibility of the method.