Improving coverage has been one of the main objectives of radio monitoring network construction, and radio monitoring coverage assessment has become a matter of concern. This article uses a graph model to associate nighttime light remote sensing (NTL-RS) data of a particular area with the corresponding spatial field strength (SFS) data obtained from an elastic wave propagation simulation. The geographic coverage and population coverage of the radio monitoring station are characterized through adjacency matrix calculation. Taking Wuhua District, Kunming, Yunnan Province, as an example, two radio services are available. Results showed that the geographic coverage of digital TV and FM radio was 21.06% and 27.96%, respectively, while the respective population coverage was 48.1% and 57.5%. When considering the light intensity weight, the weighted population coverage was 92.9% and 94.3%. The method proposed in this article is vital for the scientific assessment of radio monitoring coverage.