A scratch drive actuator (SDA), which consisted of a bushing and a plate, was one example of an electrostatic microactuator. We analysed an elastic deformation of the SDA. The analytic method of an elastic deformation caused by the electrostatic force is described. The elastic energy and the electrostatic energy were used to calculate the elastic defromation of the SDA. The obtained results were used to explain a theoretical microstep of the SDA. The method we described is applied to analyse the elastic deformation of the electrostatic microactuators.