At present, oil and gas exploration is of strategic significance to deep and ultra-deep layers. However, due to the large burial depth, which is most of them are more than 8000 m, and the degree of exploration and development is low. The phase prediction of oil and gas plays an important role in the exploration of oil and gas and the judgment of oil and gas reservoir types. In this paper, the source rock of Fengcheng Formation (P1f) in Shawan Sag of Junggar Basin is taken as the research object. With the help of basin simulation software, the thermal history of Fengcheng Formation is restored. Combined with the sedimentary burial history, the hydrocarbon generation dynamics software Kinetic is used to calculate the oil and gas phase transformation of Fengcheng Formation in different thermal evolution stages. The results show that the Ro in the early mature stage is 0.64 ~ 0.74%, and the paleogeological age is 226 ~ 208 Ma (T3-J1). The oil and gas phase is black oil reservoir. In the late mature stage, Ro is 0.89 ~ 1.07%, corresponding to 178 ~ 145 Ma (J21-J32) oil and gas phase is mainly mature oil. During the period of 95–65 Ma ago, the source rock reaches the early stage of high maturity, Ro is 1.36 ~ 1.49%. At this time, the condensate gas (oil) phase formed in the high maturity stage is mainly reserve in the source rock. During 23 ~ 0 Ma, Ro is 1.77 ~ 2.09%, Oil and gas are in condensate gas phase. The content of C1 (dry gas) is 21.1%.The content of C2–5 (wet gas) was 38.4%, the content of C6–14 (light oil) was 29.2%, and the proportion of C14+ (heavy oil) was 11.3%. It is a new idea to apply hydrocarbon generation kinetics to oil and gas phase prediction, which provides an example for future oil and gas phase prediction.