Abstract: In the field of satellite navigation, antenna delay (the delay from the antenna feed inlet to the antenna phase center) is related to the calculation of navigation application distance, and the measurement accuracy of antenna delay is related to the overall accuracy of satellite navigation. this paper proposes an antenna delay testing method based on the three-antenna method, combined with engineering applications. Starting from the basic concepts of antenna delay and phase center, this paper introduces the basic principles of three antenna method delay testing and the application of software gates in delay testing. The measurement system for antenna time delay is built in an anechoic chamber. A testing case is also shown in this paper with the three-antenna method. At last, the main error sources of the testing are analyzed. The results show that the three-antenna method has high precision, which has great significance for further study of antenna delay measurement.