[en] In order to control the quality of a nationwide survey of background external radiation dose rate, intercomparisons of FD-71 scintillation radiometers were conducted three time successively in Beijing, Nanning and Lanzhou, in May 1982, April 1983 and April 1984, respcctively. About 40 independent sanitary-epidemiological stations, background monitoring stations, institutes for prevention and treatment of occupational diseases, and research institutes of public health participated in these intercomparisons with dozens to nearly a hundred pieces of FD-71 for each intercomparison. The scintillation radiometers were calibrated under both laboratory and field conditions. Radiation levels of 27 different environmental sites for intercomparison ranged from 1.2 to 59.1 μ R/h. The data at these sites were obtained by Reuter-Stokes high pressure ionization chamber of Model RSS-111. The variation coefficient of the measured values by FD-71 scintillation radiometers fell within 5% for common radiation levels with good long term stability. The discrepancy between FD-71 and RSS-111 was within 10%