Abstract: According to a theoretical model of making high quality probe,we make the nanometric optical fiber probe that can be utilized in optical fiber biological sensor with tube etching method.This method is easy to manipulate and produce with relatively low cost.Moreover,it is not so sensitive with the experimental environment,so the repeative rate of making optical fiber probe is relatively high.The tips diameters are less than 50nm,and the taper angle 45°.We finally analyze and discuss the shape of optical fiber probe under the effect of some uncertain factors during the tube etching experiment.