Based on processing,analyzing and comparing of fault product gas Rn data from Jan.,1991 to Mar.,1994 at Jiayuguan measurement point with meteorological factors,such as geotemperature,air temperature,atmospheric pressure,wind speed,etc., it is found that influence of geotemperature on gas Rn is much less than that of air temperature and the annual variation phase of geotemperature is later than air temperature and fault product gasRn. In addition,the mechanism of influence of geotemperature on the escape of under groundgases is primarily analyzed.