The invention discloses an online monitoring and operation and maintenance device for electrical secondary equipment. The online monitoring and operation and maintenance device, by constructing an automatic access process for monitoring object online detection, automatic authentication, configuration dynamic generation and downloading, and real-time state uploading, enables the secondary equipmentto span a safe area and achieves the plug-and-play effect of a control mechanism, solves the problems of inaccurate, inconsistent and untimely information maintenance and large workloads caused by manual equipment model creation. The substation secondary equipment model automatic configuration technology provides the data model support for the remote monitoring of the secondary equipment at the substation end by adding, updating, and quitting the substation secondary equipment automatically initiated by a maintenance end.