Abstract: For the problems of small workspace and low motion accuracy of the 3T (three translational) micro-motion mechanism, an approximate complete decoupling 3-PRC type compliant parallel micro-motion mechanism with large stroke and high precision is proposed and its structure is optimized, by combining the large-stroke flexible plate unit and the highprecision flexible notch hinge. The input-output relationship of the mechanism is obtained by the vector method and the theoretical coupling errors are provided. The amplification ratio and coupling error of the mechanism are evaluated by finite element simulation. Finally, a prototype is made and an experimental platform is built. The output and decoupling performances of the mechanism are verified through experimental tests. The results show that the parallel micro-motion mechanism can achieve three-dimensional movement with the workspace of 188.75 μm×186.0 μm×185.12 μm and the maximum coupling error of 5.6%.