The invention discloses an intelligent transformer station protection vector diagnosis method based on a trend characteristic value, comprising steps of establishing correlation between a primary device interval and a relay protection device vector, establishing a primary device interval target value trend database file, reading protection vector value of the relay protection device on line in a client mode to form a state trend value database, and with the trend database file as a reference, performing difference checking on the corresponding interval trend data in the state trend database and determining to protect the vector result. The beneficial effects of the invention are that the invention can realize the automatic checking of the relay protection vector of the intelligent transformer relay protection device, can eliminate the link of manually recording the vector protection information and manually comparing the vector links in the process of vector protection test, can reduce the rates of fault diagnosis caused by manual problems, and shortens the checking time of the vector protection.