The invention provides a simulated test method of an SAR. According to the method, the SAR to be tested is fixed on the ground to work, space observation is carried out, a target flies an observation area of the SAR in set parameters and manner in the air cooperatively, the flight track and attitude of the target can be observed, measurement is carried out synchronous with work of the SAR, and measurement parameters are recorded at the same time. According the method, simulated test for the SAR is realized by approaching practical flight condition of the SAR as possible, the cost and risk of SAR test are reduced greatly, and the simulated test method is especially suitable for testing SAR systems in which real trial flight of a missile-borne or spaceborne SAR cannot be realized.