The quality and the efficiency of the polishing process are important to the lead time of the rapid tooling. Robotic polishing process with free abrasive is adapted to the finishing of complex mould surface, in which the soft polishing tool is widely used. But the stability and the efficiency of the process should be improved further. According to the moving and grinding characters of the free abrasive, the mixed magnetic abrasive and the minitype electromagnetic field are combined to the robotic polishing process. The mixed magnetic abrasive are made up of magnetic grain and hard abrasive, which can enhance the effective cutting and grinding process of the three-body abrasion under the effect of magnetic field. The robotic compound polishing process with mixed magnetic abrasive is presented in this paper. The experiments are tested to study the distribution of the minitye magnetic field and the polishing efficiency of the complex polishing process. The results show that the polishing efficiency of the process can be improved obviously where the effective working intensity of the electromagnetic field reaches 400Gs.