There is a high incidence of lung cancer in Gejiu area of Yunnan Province. Using method of SSNTD (solid state nuclear track detector), 469 data of radon in the indoor or soil have been obtained. There is 471.9 Bq•m^-3 on an average in houses situated in geologic fault zone. None of ore of uranium or thorium has been found here. The migration of radon seems not "diffusion" but "suction effect".