Abstract: China is carrying out the construction and preconstruction of large aperture spherical radio telescope and array radio telescopes. In order to guarantee the pre-construction work of radio telescope, it is necessary to find a station site that meets the requirements of electromagnetic environment firstly, and electromagnetic environment monitoring is carried out in candidate sites such as DuBu Town and Shuikou Town of Yangshan County, Qingyuan City, Guangdong Province, by using moving electromagnetic environment monitoring equipment, and comparative testing is carried out on MaoFeng Mountain of BaiYun District, Guangzhou City, and electromagnetic environment monitoring data are analyzed by using a method of judging the threshold value of the interference. The analysis results show that the depression located near DuBu Town, Yangshan County, Qingyuan City, has a low number and weak intensity of radio-frequency interference, which is far away from the city center, has few economic activities, is surrounded by mountains, and has good electromagnetic isolation, which is suitable for the construction of large aperture spherical radio telescope and array radio telescopes. The results of the data analysis in this paper can provide a basis for the site selection of large aperture spherical radio telescopes. In the future, the establishment of a radio quiet zone in the depressions and within a reasonable range near Dubu Town can be considered to protect the existing electromagnetic environment.