Abstract: In this paper,the natural gas characteristics of well Chaishen-1 are described.And the genetic types of natural gases are approached using the carbon and hydrogen isotope research method of mathane and its homologues.Meanwhile,the gas sources have also been traced and explored preliminarily.The natural gas of this well,which belongs to condensate gas formed by the humic mother material of high maturity stage,has affinity with the Hongyanchi Formation and Lucaogou Formation of the Upper Permian.