Abstract: The pointing accuracy of phased array antenna determinates the detection accuracy of radar system, and even effects the success or failure of tracking and intercepting target. Taking a kind of ground-based phased array antenna as an example, the sources of systematic pointing error in the electromechanical hybrid scanning antenna are detailed including 1) the distance error between antenna units caused by thermal deformation, 2) air refraction, 3) mechanical error during azimuth rotating, 4) temperature field distribution within the antenna. In this paper, the influence of the above factors on the antenna pointing accuracy is analyzed theoretically, and the complete remote field error calibration method and error correction process are proposed. The experiment results show that the error sources analysis is correct. And also, the proposed calibration method can greatly improve the antenna pointing accuracy. Thus, the tracking accuracy and the power of radar system are obvious improved. It has the important reference value for the design and application of ground-based and mobile-platform phased array antenna.