In this study, a basic gait motion simulator mechanism combining control units and electromechanic hardware has been proposed and implemented for the test stages of knee prostheses. The main goal to develop such simulator equipment is to regenerate predefined and controllable periodic movement, specifically hip vertical displacement and thigh angle motion applied to above-knee prosthesis so that test studies will be less dependent to human trials in any development phase. Gait motion simulator performance tests were conducted with both an image-based motion measurement system and a direct-type motion measurement system. In the hip simulator performance evaluation phase, accelerometer and video signals were collected simultaneously from the experimental system for kinematic analysis. The overall system consists of a hip simulator, a microcontroller-controlled prosthetic knee and a solid ankle cushion heel foot on a treadmill. Experimental results were evaluated for assessing the degree of approximation of the natural periodic hip movement by designed electromechanical simulator. The analysis showed that the test platform presented in this study is a useful yet low budget alternative to more expensive general-purpose electromechanic test devices for development purposes.