According to the hydraulic transmission principle, a device for fabricating large cone angle near-field optical fiber probe by means of dynamic chemical etching is developed. The results indicated that in the course of traditional fabrication of optical fiber probes by chemical etching, the configuration and the cone angle of the taper can be controlled efficiently through controlling the velocity of the lifting of etching fluid. Furthermore, The advantage of controlling the displacement between optical fiber probe and etching fluid step by step in the fabrication of large cone angle optical fiber probe is also described in this paper. A large cone angle near-field optical fiber probe in scanning near-field optical microscopy is applied to measuring the sphere with a diameter 200nm. Its force images show that this probe has high topography resolution (～50nm).