The quality control of satellite observations has shown significant impact on data assimilation as well as retrieving meteorological products.Satellite microwave thermal emission mixed with signals derived from the active sensors,e.g.radar technologies,air traffic control system,garage door opener remote control,applications of the global positioning system to intelligent vehicle highway systems,defense transportation tracking system,vehicle speed detection system,etc., is referred to as radio-frequency interference(RFI).RFI remarkably causes serious problem for microwave sensing. Comparing with previous advanced microwave scanning radiometer-EOS (AMSR-E),AMSR-2 which is on board the global change observation mission 1st-water(GCOM-W1) satellite, and adds the channels at 7.3 GHz, in order to mitigate the RFI contamination at lower frequencies.AMSR-2 has seven frequencies at 6.9,7.3,10.65,18.7,23.8,36.5,and 89.0 GHz,each having dual channels at vertical and horizontal polarization states, respectively.In order to analyze the observations at this new-added channel be interfered or not,RFI at 7.3 GHz over East Asia is identified using spectral difference method based on AMSR-2 observations collected from August 1st to 16th,2014. The achieved results showed that RFI at 7.3 GHz widely spreads over East Asia in some places.The RFIs located in Gyeonggi-do Province,South Korea,Bangladesh,Vietnam and,South-East Cambodia are isolated in space and persistent in time and originate from a wide variety of coherent point target sources.The observations of spaceborne microwave radiometer in ascending orbit portions usually are interfered over Japan,while no RFI approximately was detected in descending portions. The RFI location and intensity varied with time and radiometer scanning angle within observation period.After analyzing the contamination source, it can be concluded that the source of RFI in Japan is the results of the interference of the reflected geostationary communication or down linked satellite signals with the spaceborne microwave radiometer data.