The principle and key technologies of the optic real-time signal process system for synthetic aperture microwave radiometer were analyzed. An infrared real-time signal process system prototype for an X-band synthetic aperture microwave radiometer with six elements was developed. The system tests and one dimensional imaging experiments of point source were carried out. The clear interference fringes pattern were obtained. The primary experiment results validate the feasibility of real-time signal processing for synthetic aperture microwave radiometer and the correctness of the system design.