The invention discloses a temperature self-compensated fiber grating strain sensor which comprises a fiber grating, a substrate, compensation blocks, a fixed block I, and a push mechanism. The compensation blocks are arranged at one end of the substrate. One end of the push mechanism is fixed on the fixed block I, and the other end is hinged to the compensation blocks. The fiber grating is fixed on the substrate through the fixed block I. The substrate is provided with a guide chute. The fixed block I can slide in the guide chute to drive the push mechanism to move along the arrangement direction of the fiber grating. The sensor has a simple structure. The influence of temperature can be automatically eliminated the in the process of strain measurement. The demodulation is simple. The measurement result is more visual. No data operation related to temperature compensation is needed.