A novel microactuator in horizontalplane is designed, which has the features of simple structure, fast response and large output displacement. The fininte element model was built based on ANSYS, the ydiretion and zdiretion deformation figures are obtained through piezoeletric analysis, theydiretion dispacement and zdiretion displacement value of the driving end is 0.61 μm and 1.13 μm respectively. Through the modal analysis the first five nature frequencies and three nature mode shapes are gained, the resonance effect on the microactuator can be seen from the nature mode shapes. The parametric study of the critical size is carried out. It can provide a theoretical guaidance for the future design of microactuator.