In this study, a simple wet etching technique is developed for the fabrication of a high-sensitivity plastic optical fiber (POF) refractive index sensor. Firstly, the etchant was prepared by employing the chloroform and anhydrous ethanol. Secondly, the effects of the concentration and temperature of the etchant on the etching rate and surface morphology of the POFs were investigated, and the transmission spectrum of the etched POF sensors was examined. Thirdly, the sensitivity of the etched POF sensors was checked by using the glucose solutions. The experimental results show that the etching rate of the POFs increases with increasing of the etchant’s concentration and temperature. The surface morphology, transmission spectrum and sensitivity of the etched POF were significantly affected by the etching conditions, in particular, the POF sensors, which are fabricated using the etchant with a concentration of 70% under temperature of 20℃, exhibiting good light transmission and a high sensitivity of 3.8[(RIU)]-1 in the glucose solutions.