In recent years, there has been a demand for further performance improvement of internal combustion engines from the viewpoint of reducing environmental impact. The combustion state of an engine is affected by the parameters of the dynamic valve system, such as the opening and closing timing and the lift of the intake and exhaust valves. The valve motion is constant because it depends on the cam geometry, and depending on the engine operating conditions, fuel consumption and power output are affected. Therefore, our research group focused on an electromagnetic valve driven system (EVDS). In this study, four models were created to improve the magnetic circuit of a linear actuator. To investigate the thrust characteristics of these actuators, electromagnetic field analysis was performed using the finite element method. In addition, electromagnetic field analysis was conducted using materials with different saturation magnetic flux densities to investigate the effects of changing the yoke material on the magnetic flux flow and thrust.