At present, cloud computing, as a strategic emerging industry in China, has greatly promoted the development of informatization. Although State Grid Corporation of China’s regulation cloud construction is steadily advancing, there is no effective security protection in the face of illegal access, virtual machine escaping, abnormal operation traceability, etc. In this paper, a security monitoring system based on the cloud platform is designed to achieve the comprehensive real-time monitoring of cloud platform security events of the hosts, virtual machines and cloud management software, timely identify of security threats with early warnings, and guarantee the operation of the cloud platform in security, through the investigating and in-depth research on the security monitoring technology of key components of the cloud platform.