The design, properties and optimization of an ultrasonic actuator are presented. Numerical modeling has been carried out and simulations with the FEM Ansys software have been realized. To avoid performing a large number of simulations, input parameters like geometrical dimensions, material properties or even boundary conditions can be judiciously chosen in function of their influence on the output parameter (deformation amplitude). In this manner, sensitivity of each input parameter on the output parameter value can be achieved, in particular using design of experiments. Factorial designs and Doehlert method have been chosen. The results found show that this pre-optimization stage allows one to improve the deformation amplitude but also to reduce the input parameter variation ranges. Different optimization methods using Ansys are then applied and results show that the deformation amplitude can even be more increased compared to the initial design.