Abstract: By analyzing the experimental data and the problems in fault gas radon measurement, this paper comprehensively discusses the influences of geological factor and meteoroiogical factor on fault gas radon measurement. We have analyzed the relation between the shape of fault gas radon and the fault property and the influences of rock soil property, water content in soil, air temperature, ground temperature, atmospheric pressure on soil radon measurement, It is pointed out that if only we fully recognize and pay attention to avoiding or eliminating above influence factors, we can obtain relatively satisfactory gas radon measurements.