Abstract: Kaolinite is widely developed in Liushagang formation of Wushi sag,which has an important influence on reservoir physical properties.By taking the kaolinite in Liushagang formation sandstone of Wushi sag as the research object,the distribution characteristics,influencing factors and evolution rules of kaolinite were analyzed by means of thin section,SEM,cathodoluminescence and X-ray diffraction.The results show that in vertical direction the content of kaolinite is the highest in the first member of Liushaguang formation,the second in the second member,and the lowest in the third member.In the plane,the content of kaolinite is the highest in WSA area,the second in WSC area and the lowest in WSB area.There is a close relationship between kaolinite and high-quality reservoir.The main factors affecting the distribution of kaolinite are temperature and pressure,structural movement,lithologic differences and source properties.Based on the analysis of feldspar dissolution and kaolinite differential precipitation,the sweet spot development model of kaolinite developed reservoir was established.