Paddy harrow machine used hydraulic actuator system has been changed to the electric actuator system method. Because driving system of the agricultural equipments has been changed to electric power system. Besides, the effort to reduce the tractor machine's horse power is proceeding rapidly. In this paper, pressure, load scale factor and loading force(dynamic, static force) are considered to determine the cylinder diameter of the electric actuator. The algorithms of paddy harrow machine was studied to control and test the components of link by using the PLC diagram. Also, the electric actuator mechanism system was evaluated through the PLC algorithm. These test results can be attributed to select the actuator capacity and to determine the reliability of the electric actuator system