A temperature fiber sensor based on Ma ch-Zehnder (M-Z) interferometer with waist-enlarged fusion bitapers is propos ed.It′s enlarged at each end of a 4.5cm-long single mode fiber that achieves the M-Z interferometer by cascading two spherical-shaped single mode fibe r structures with the technology of waist-enlarged fusion.This interferometer has temperature-sensitive features,so the effective refractive index of the cladding mode changes with the external temper ature,and then the interference transmission spectra change accordingly.By observing the character istic wavelength shifts of the same interference dip order,temperature can be measured.Experimental results show that when the temperature changes from 15℃ to 60℃,the interference spectrum has an obvious red shift,and the relevant sensitivity of sensor is 0.068nm/℃.The temperature fiber sensor has many advan tages,including simple structure,low cost and high sensitivity.Therefore,it has great potential for mea surement of temperature.