The invention provides an event storage method and device for a comprehensive monitoring system based on rail transit, and the method comprises the steps: receiving event subscription information sentby an event server through an OPC UA standard interface; Obtaining corresponding real-time data from a comprehensive monitoring system according to the event subscription information; Judging whetherthe real-time data meets a trigger condition or not according to a preset event rule corresponding to the event subscription information, and generating corresponding trigger event information if thetrigger condition is met; And sending the trigger event information to the event server through the OPC UA standard interface. Thus, on one hand, The OPC UA is used as a communication server of a comprehensive monitoring system and an event server of rail transit. and on the other hand, events are collected on the basis of operation of the OPC UA server, the stability of event collection is guaranteed, generation and collection of the events are separated, and system maintenance and upgrading are facilitated.