The invention discloses a network security monitoring system applied to a power monitoring system, and belongs to the technical field of network security monitoring systems. The network security monitoring system comprises a dispatch control system, a substation monitoring system, a power plant monitoring system, an automatic power distribution system and a load control system, output ends of thedispatch control system, the substation monitoring system, the power plant monitoring system, the automatic power distribution system and the load control system are electrically connected with an input end of a distributed collection module, the output end of the distributed collection module is electrically connected with the input end of a network security management platform, real-time monitoring and effective management of network space security are achieved through the independent collection of network security events of various monitoring points and the distributed processing of data, real-time monitoring and online management can be performed on the security risks and the security events of the power monitoring system to avoid the problem that the whole system cannot run due to a single point fault, the subsequent expansion and maintenance are facilitated, and the security coefficient is high.