A novel symmetric scratch drive actuator (SSDA) capable of two-way motion is proposed here. An analysis scheme is presented, and also can be applied to the conventional scratch &ire actuator (SDA). The analysis derived here is the first to be able to relate the step increment and driving voltage with given geometrical parameters and material properties for SSDA or SDA. In order to verify the analysis, the simulation results are compared to experimental data of SDA in previous literature , and it shows good agreement. In the analysis of SSDA, it is found that SSDA can provide the same order of step increment with the same driving voltage, and it may move in two directions by one device.