Abstract: In order to improve the temperature sensitivity of photonic bandgap fiber,a new structure was proposed merging high refractive index liquid cylinders into the surround of the fiber core.By means of full-vector finite element method,the influence of temperature on the effective refractive index,core energy,effective mode area was obtained.The numerical results show that when the temperature increases,the effective refractive index and the effective mode area decrease,the core energy increases,and the zero dispersion wavelength moves towards longer wavelength.These changes are quite significant when the wavelength is short.The proposed structure improves the temperature sensitivity of the transmission characteristics,which makes photonic bandgap photonic crystal fibers more suitable for temperature sensing applications.