A novel periodic micro-tapering glass fiber based on rare-earth-doped glass fiber and its bending sensor application are investigaled. The material of fiber consists of two types of lead silicate glasses, one is for core, and the is for cladding. And it has the performances of good plasticity and easy taper. The key body of the sensor is made of the rare-earth-doped fiber which is heated by the focused CO2 laser beam in periodic and equal spacing. In this paper we constructe an intensity modulated bending sensor measurement system based on the sensor body, high resolution moving platform and optic testing platform. Principle research and experiment testing show that the designed bending sensor measurement unit has a high bending sensitivity of -28.2W/m and a low measurement error of lass than ± 1%, which is of significance for possible applications in engineering.