Typical hydraulic system, although it is widely applied in industry because of its high energy density, its actual operational efficiency is only 23%-25% owing to very high energy losses, such as pressure loss and fluid dynamics loss, caused by the hydraulic system. An electro-hydrostatic actuator (EHA) system is a compact system in which an electric motor and hydraulic pump are incorporated into a cylinder, which results in greater energy efficiency than conventional hydraulic systems. The EHA system also suffers from relatively less leakage than valve-operated systems. This system consists of a bidirectional pump and a hydraulic cylinder operated by an electric motor, which adjusts the discharge flow rate of the pump by controlling the speed in both directions and changes the forward or backward direction and speed of the hydraulic cylinder accordingly. In this study, the characteristics of a single-rod cylinder load operation system, an EHA hydraulic circuit, and an electric motor are analyzed using mathematical models, and the performance of a closed-loop hydraulic control system incorporating an EHA with a rotation angle of a base plate controller is investigated.