The invention discloses a fiber grating monitoring system for a power transmission line, which comprises a fiber grating sensing module, a transmission module and a computation module, wherein the fiber grating sensing module is used for receiving a first optical signal transmitted from the transmission module, and transmitting a second optical signal after the reflection of the first optical signal to the computation module through the transmission module; the transmission module is used for transmitting the first optical signal and the second optical signal; and the computation module is used for acquiring the pulling force borne by the power transmission line and the inclination angle of the power transmission line according to the change of the center wavelength of the second optical signal relative to the first optical signal, and acquiring the ice cover of the power transmission line according to the pulling force and the inclination angle.