Abstract: A new microwave millimeterwave amplitude phase measurement system and its applications are presented in this paper. Compared with traditional system, it is typical of novel principle, simple construction, easy frequency band expansibility and convenient applications. So far, it has been applied in many fields, such as CATR electric performance testing, antenna pattern measurement and RCS measurement, with the band covering from 1GHz to 110GHz. This system has been patented and appraised by the government.