The invention discloses a temperature self-compensating fiber grating micro force sensor and a manufacturing method thereof. The sensor comprises a force-bearing end cover, a sensor upper shell, a sensor lower shell, a hard core, a supporting cylinder and a round elastic diaphragm, wherein the hard core comprises a hard core screw and a hard core nut; the top part of the supporting cylinder passes through the sensor upper shell, and the bottom part is fixed with the hard core screw; the supporting cylinder is internally provided with a fiber, a first fiber grating and a second fiber grating are carved on the fiber, one end of the first fiber grating is fixedly connected with the top part of the upper shell and the other end is fixed with the hard core screw and is in a tensioning state, and one end of the second fiber grating is connected with the lower part of the hard core screw and the other end passes through the sensor lower shell and is in a free elastic state. The structure is simple; the force measurement sensitivity and the force measurement range of the sensor can be changed in a large range, production and manufacturing of batch sensors with multiple specifications are facilitated; temperature self compensating can be realized; and long-term and reliable effective monitoring by the sensor in a temperature-varying environment can be realized.