In order to protect Fiber Bragg Grating (FBG), a non-coarsening fiber surface electroless plating and electroplating technics with good adhesion force between layer and fiber was proposed. Based on stress analysis, the temperature sensitivity of protected FBG was achieved in theory, the stresses on the protected FBG under varied temperatures were analyzed by a finite element analysis software (ANSYS) and verified by experiment. The results show that the temperature sensitivity of protected FBG is 20.6951 pm/℃ theoretical and 22.076 pm/℃ from the experiments, which the results of theoretical analysis match the ones from experiments and simulations very well. The temperature sensitivity is 2.2 times as much as that of bare FBG. The desirable thickness of metallic protect layer can be obtained and the temperature sensitivity can be improved.