There is a phenomenon that the temperature variable and the strain variable cross influence the center wavelength of the fiber grating in fiber grating load cell.In order to compensate the influence of the temperature variable on the center wavelength of the fiber grating,a double- grating method was proposed to correct the deflection of the central light wavelength caused by the temperature variable.The experimental measurement results of the fiber grating center light wavelength measurement test under different forces and different temperatures are consistent with the theoretical calculation results,which indicate that the double-grating method application for force measurement is effective.