A novel fiber grating temperature sensing technique and its experimental result is reported,which eliminates the chirped effects of polymer-packaged,improves the reflection spectrum of FBG and the technique of repeated packaged by using a kind of polymer-packaged with biggish thermal expansion coefficient and a special coupling agent. The experimental result indicates that ,within 30.6℃~120℃ ,the temperature sensitivity is 0.1173 nm/℃ and the resolution temperature measurement is <0.43℃,which are 11 times higher than that of the bare FBG and the most important advantage is that the reflection spectrum remains same in the whole test.The average temperature sensitivity multiple of polymer-packaged fiber Bragg gratings is γ′=10.34,which matches the theoretical multiple γ=10.76 well. The linearity of the temperature response curves is 0.9983.