Abstract: The condensate gas reservoir is a particular gas reser- voir of high economic value.The development of condense gas pool is closely related to the phase state character of the oil and gas system,because the phase state characters deter- mine the division of development stages,the establishment of development policy,and the prediction of the normal pro- duction index of oil wells and gas wells.Case studies are presented to introduce the testing and fitting of PVT analysis on the oil and gas system,and the methods to distinguish the fluid type.