In order to publicly notify the information security (Internet or Cyber) threat level, the security companies have developed the Threat Meters. As the physical security devices are getting more intelligent and can be monitored and managed through networks, we propose a physical security threat meter (PSTM) to determine the current threat level of physical security; that is a very similar compared with the one of information security. For this purpose, we investigate and prioritize the physical security events, and consider the impact of temporal correlation among multiple security events. We also present how to determine the threshold values of threat levels, and then propose a practical PSTM using the threshold based decision. In particular, we show that the proposed scheme is fully implementable through showing the block diagram in detail and the whole implementation processes with the access controller and CCTV+video analyzer system. Finally the simulation results show that the proposed PSTM works perfectly under some test scenarios.