Based on the advanced microwave scanning radiometer 2 (AMSR2) first level brightness temperature data, the influence of radio frequency interference (RFI) signal on AMSR2 7.3 GHz channel measurement data over East Asian Ocean is evaluated with generalized RI index identification method, and the results are compared with those obtained by spectrum difference method. The results show that the location and time variation characteristics of the RFI signal contamination detected by the two methods are almost the same, but the RFI signal detected by the generalized RI index recognition method has larger intensity, wider range and more pixels. At the same frequency, more RFI signals are observed by vertical polarization than by horizontal polarization. The distribution of RFI signals over East Asian Ocean shows a long and narrow strip with a northeast to southwest trend, and its position and range vary with the observation time. For AMSR2, the 7.3 GHz RFI signal on the ocean surface only appears in the descending orbit observation and is mainly from the downlink signal of the stationary satellite over the equator reflected by the ocean surface.