Abstract: The development of radio astronomic observations requires increasingly wide frequency band.However, with the continuous development of radio communication system, the radio frequency interference (RFI) has also become a curial factor which requires the sites for radio telescopes to be checked carefully for the RFI.In this paper, a method of data analysis and processing for the electromagnetic environments test is built, with which the results are presented for those telescopes that are under construction and those are in the preparatory phase.Lots of campaigns have been carried out to find excellent electromagnetic environment for the telescope site, it concludes that those sites with good electromagnetic environment conditions should be well protected.