A curvature sensor is proposed base on tapered photonic crystal fiber(TPCF) Mach-Zehnder interferometer. A section of PCF is tapered after splicing both end of it with single-mode fiber(SMF), then a SMF-TPCF-SMF structure with 20 mm length is fabricated. By controlling the arc discharge parameters, the air holes of the PCF near the splicing area are collapsed completely. So it can motivate the cladding modes better. Moreover, the splicing and tapering length of PCF are determined to make the sensor produce high curvature sensitivity. The experimental results show that the transmission spectrum of sensor appears blue shift obviously with the curvature increasing, and the shift of the peaks near 1590 nm is -6.06 nm. The curvature sensitivity of this sensor is -5.39297 nm/m-1 in the range of 0~1.16 m-1 curvature, and this sensor also has good linearity. This curvature sensor has the advantages of simple structure, easy manufacturing, high sensitivity and immune to the temperature cross-sensitivity compared to other sensors, so it can be used for measuring curvature in bridges, buildings, roads and so on.