The rapid development of the mobile Internet and 5G technology has made the Internet of Vehicles possible. Through V2X technology, mobile vehicles can exchange information with roadside units and cloud-side applications. A vehicle with networking capabilities is called an intelligent connected vehicle (ICV). The emergence of ICVs allows people to experience the enjoyability of intelligent driving and the convenience of massive Internet applications. At the same time, networking breaks the closed control system of vehicles and introduces new network security issues. In recent years, attacks against ICVs have continued to occur, and network security issues have received widespread attention. Currently, passing security tests has become a necessary condition for ICVs to obtain sales licenses. However, due to the lack of complete infrastructure and testing methods, security testing of ICVs is still challenging. We propose a security testing method for ICVs based on the cyber range. By placing an ICV in an emulation environment constructed with a cyber range, security penetration testing is performed to analyze the potential security risks and vulnerabilities of the target vehicle. Conducting security evaluations of ICVs based on the cyber range can effectively extend the security testing time of vehicles and ensure the comprehensiveness and effectiveness of the test results. This article also introduces the architecture, application scenarios and testing process of the ICV cyber range. At present, this security assessment method for ICVs has been applied in the production processes of Chinese automobile manufacturing companies.