A model reference adaptive controller is designed and implemented in a microcomputer to control the position of a servohydraulic variable piston motor in this article. To satisfy the specification of a desired output, an adaptive controller is designed according to the model reference following adaptive control method. The time response of Bessel's third-order prototype is chosen as the reference model. The effects of different uncertain parameters of the system are tested and shown. In addition, the experimental results with the PID-, the proportional model-following and the model-following optimal controller are compared to those from the adaptive controller.