In this paper, a temperature compensated hydrophone based on fiber Bragg grating (FBG) is developed to meet the requirements of sound detection in different temperature in marine environment. The hydrophone is sensitized by the side stretch structure, and the structure of hydrophone is optimized by the finite element analysis method. In this structure, the compensation material Polymethyl methacrylate(PMMA) is used, and its thermal expansion effect is used to modulate FBG, so as to reduce the impact of temperature on FBG and realize temperature compensation. The simulation results show that the structure can achieve higher sensitivity in the range of 10~2000 Hz, and the sensitivity gain spectrum of the hydrophone shows resonance characteristics. Compared with the place far away from the resonance frequency, the sensitivity gain is further improved, reaching 145 dB at most. In the range of ocean temperature (-2 ℃ ~ 30 ℃), the temperature compensation of wavelength shift less than 0.01006 nm can be realized.