Abstract: On the guidance of reservoir geology,logging geology,oil-gas field development geology and related principle,the fine division of small layers on Triassic Chang6 formation in LF area of Ordos basin have been made.The source rocks,sedimentary facies,sand body characteristics,structural feature and reservoir characteristics etc,the main controlling factors of Chang6 have been systemically researched.The study results indicate that the thick source rocks is the foundation of the hydrocarbon accumulation and underwater distributary channel,the debouch bar microfacies is the favorable oil phase belt of Chang6 section,the uplift high place is the favorable structural parts of hydrocarbon,the high degree of the closed nose-like uplifts plays an important controlling role on reservoir forming,good cap rock is the important condition of reservoir forming.Optimized favorable petroleum zones based on the above method provide good guidance for the further explorative deployment in LF area.