Formal modeling and verification of a concurrent system is an essential means to ensure the security and reliability of the system. However, at present, there is no single formal method that can fully meet the modeling and verification requirements of concurrent systems. In this paper, we propose an integrated formal method that utilizes both event-based method Event-B and state-based formalism LTS to address this problem. We first analyze the difference and connection between Event-B and LTS in building system models and then propose to use the graphical front-end iUML-B of Event-B to obtain a unified representation with LTS so as to take their advantages in the integrated method. Finally, we carry out a case study to demonstrate the practicality of the proposed method. The case study shows that our method effectively models and verifies the various properties of the system, and to a large extent makes up for the shortcomings of a single formal method in the process of system modeling and verification.