A high-voltage circuit breaker actuator is composed of a solenoid actuator, a pilot valve and a hydraulic cylinder system, and the solenoid actuator and the pilot valve are limited by a force amplifier which has a function of a lever. The response characteristics of a solenoid actuator are very important parameter because a high load occurrence of the high-voltage circuit breaker and a high speed operating is accomplished simultaneously. A solenoid actuator is a component which transfers from an electrical signal to linear mechanical movement, and is also used for several industrial fields such as valves, switches, relays, OA and FA because a structure is simple and a precise control is capable. The multi-physics analysis which considers a kind of nonlinearity of magnetic material, an eddy current, circuit equations by power source and movement equations with a plunger displacement for a solenoid actuator design is needed because this is operated under the condition of a transient state though the input source is DC power.1∼3In this study, some parameters to infect to the solenoid performances are analyzed using the transient state problem. An electromagnetic characteristics and dynamic characteristics are also analyzed for the performance evaluation of the solenoid actuator for high-voltage circuit breaker. And, the parameters such as solid type plunger and laminated plunger which are related to performance improvement were investigated.