A novel approach for simultaneous measurement of temperature and pressure using a single fiber Bragg grating (FBG) based on reflected wave's broadened bandwidth is proposed and demonstrated. FBG is affixed on the non??uniformity strain area of double??hole cantilever beam by special polymer. Bragg reflected wavelength is shifted and reflected bandwidth is broadened by pressure change, while temperature change just leads to the shift of reflected wavelength. In the temperature range 20～100 ℃ and pressure range 0～7.8 N, the precisions of temperature measure and pressure measure are ±1.1 ℃ and ±0.18 N respectively. The response curves of FBG have good linearity which are higher than 99.6%. Reflection spectrum has a steady figure through repeated measurement.