Because the performance of the existing fast tool servomechanism was difficult to meet the processing capability and accuracy requirements for non-rotating components with micro-structure array surfaces， the giant magnetostrictive actuator （GMA） was integrated with the motorized spindle. A design scheme for a micro-structure precision machining mechanism for the electric spindle was presented. First， the influence of the GMA driving magnetic field on the spindle motor magnetic field was analyzed. Second， the electromagnetic-mechanical coupling model and the force sensing model were established， and the influence of bias current and prestress on its performance-as well as the variation law of force sensing characteristics under different bias currents were analyzed. Finally， the performance test platform was built and verified through experiments. The results show that the excitation magnetic field of GMA is only 4.09% of the driving magnetic field of spindle motor； The addition of appropriate bias current and prestress is beneficial to improve the output displacement of micro-structure precision machining mechanism， and the experimental and simulation results verify the validity of the theoretical model. The force sensing simulation results are consistent with the calculation results of the force sensing model， and the output voltage and the axial force of the main shaft show a first-order derivative relationship. The experimental results show that when the bias current is 1 A and the prestress is 1 MPa， the output displacement can reach 26.2 μm and the output thrust can reach 22 N， which indicates that the design scheme of the micro-structure precision machining mechanism oriented to the electric spindle is feasible and provides a solution for the machining of complex micro-structure components.