Based on the viscosity control of magnetic compound fluid, a method and process for the polishing of micro-nano structural surfaces were presented in order to obtain a micro-nano machining technology with low cost and controllabitity and apply it in the teaching experiment of micro-nano machining. Using the magnetic compound fluid as the polishing fluid, two kinds of magnetic compound fluid polishing equipments were designed. According to the characteristics of the surface structure of micro grooves, the circumferential type magnetic compound fluid polishing equipment was used to perform the microstructure surface finishing experiments. By designing the polishing process and comparing the effect of the surface machining of micro groove fringes, the experimental device and the method for microstructure finishing were validated. The device for magnetic compound fluid polishing has a simple structure, low cost in use and maintenance, which is suitable for widely use in the experimental teaching of micro-nano machining in mechanical manufacturing courses.