The invention discloses an electrical axis optical calibration system of a spaceborne microwave tracking-pointing radar and a calibration method of the electrical axis optical calibration system. The electrical axis optical calibration system comprises a radar testing subsystem, a calibration subsystem, a radar device and a target simulation subsystem. The target simulation subsystem comprises a target simulation source, a two-dimensional testing rotary table, a two-dimensional testing rotary table controller connected with the two-dimensional testing rotary table, a two-dimensional scanning frame and a target simulation horn antenna arranged on the two-dimensional scanning frame. The calibration method comprises the first step of calibrating the mounting precision of a radar antenna and a driving mechanism, the second step of calibrating the consistency of a radar electric axis and a radar antenna mechanical axis and the third step of correcting the radar according to a calibration result. According to the electrical axis optical calibration system of the spaceborne microwave tracking-pointing radar and the calibration method, high-precision calibration can be carried out on the radar in a compact field, the requirement of the radar for the temperature, the humidity and the cleanliness of used environment is met, the non-contact calibration of the spaceborne microwave tracking-pointing radar is achieved, the used measuring instruments are small in number and high in precision, the calculation of data can be automatically completed, and the high precision and the high reliability of the radar are guaranteed.