The invention discloses a guard system of transformer substations. The system comprises a master station system which is installed in a monitoring center and sub station systems which are installed in transformer substations, wherein the master station system communicates with the sub station systems through a network. The system disclosed by the invention satisfies a series of requirements such as high reliability, networking, remote vision, remote photographing, remote recording, remote talkback, automatic tracking, coordinated tracking and automatic calling required by power enterprises, and realizes an intelligent electronic security monitoring platform with application requirements such as remote guard and remote security, so that the supervision strength of the transformer substations is improved and the human resources are further saved.