Abstract: In this paper,the principle of the measurement for the quiet zone performance of a microwave anechoic chamber is presented.Detailed measurement procedures to an actual rectangular chamber using a log-periodic antenna and vector network analyzer are simultaneously given.The method and steps provided here are valuable for building,using and maintaining a microwave anechoic chamber,and also useful for the reference to the measurement of antennas and microwave backward scattering conducted in the chamber.