The temperature sensing characteristics of the Total Internal Reflection Photonic Crystal Fiber（TIR-PCF）with the air hole as the positive nine side shaped periodic array is investigated by using the full vector finite element method.The effects of different air hole arrangement

duty cycle and wavelength on the temperature characteristics are analyzed and compared with the photonic crystal fiber with hexagonal structure.The result shows that the PCF mode field distribution changes significantly with the change of temperature.The effective refractive index and the limitation of the size of the air hole is inversely proportional to the temperature of the air hole in the positive nine shape periodic arrangement.Keeping the distance between the holes constant

the results show that the larger the duty cycle or the longer the input wavelength

the higher the sensitivity will be.Then

we propose a kind of the positive nine side shaped periodic array and fusion point for cone SMF-PCF-SMF（Single-Mode Fiber

SMF）Mach-Zehnder Interferometer（MZI）temperature sensor.The result shows that when the wavelength is 1 550 nm and the duty cycle is 0.6

the temperature range from-20 to 80℃

and the temperature sensitivity of the sensing structure is0.112 2nm/℃.