In order to improve the application of FBG in high temperature conditions,FBG was coated with copper and nickel by an electroless-electro plating method.The failure temperature of the metal-coated FBG was studied.During 300~900 °C,the temperature sensitivity,spectral characteristic and power attenuation of the metal-coated FBG were systemically analyzed.Results show:(i)the average temperature sensitivities of Cu-coated FBG,Ni-coated FBG,and bare FBG were respectively 15.35 pm/°C,16.34 pm/°C,16.1 pm/°C during 300~800 °C;(ii)the failure temperature of metal-coated FBG is about 900 °C,which is 100 °C more than that of bare FBG;(iii)the spectral characteristic and power attenuation of FBG were obtained during the high temperature failure process.