A high birefringent hybrid lattice Photonic Crystal Fiber（PCF）with modified circular and rectangular air holes is proposed.When the air holes are filled with the thermo-sensitive fluid

the variations of its birefringence properties with temperature are investigated by using the finite-element method-based Comsol software.The research results show that when the circular air holes in the core area are filled with ethanol and the pitch of holesΛ =1μm

the diameter of circular air holes D =0.96μm and the aspect ratio of rectangular air holes a/b=4

the thermo sensibility of the PCF at excitation wavelengthλ=1 550 nm reaches 10-5.The proposed fiber has broad application prospects in PCF temperature sensors with high sensitivity.