Abstract: The reservoirs from the third member of Liushagang formation in the X oilfield of Wushi sag is complex and sensitive. In this study, a variety of analytical methods, such as thin section identification of rock, X-ray diffraction of clay minerals, scanning electron microscopy, high-pressure mercury injection, are used to carry out the reservoir sensitivity test, so as to analyze the reservoir sensitivity regularity and sensitivity damage mechanism, and provide a basis for efficient development of the oilfield. The experimental results show that the water sensitivity of Glutenite reservoir is very strong, and the water sensitivity of fine sandstone reservoir is medium to strong; the velocity sensitivity of Glutenite reservoir in single-phase brine is medium, the critical velocity is 0.965 m/d, the velocity sensitivity is weak in single-phase neutral oil, there is no critical velocity, and the fine sandstone reservoir has no speed sensitivity; the overall acid sensitivity of the reservoir is medium to weak, and the alkali sensitivity is weak. The content, type, occurrence and pore structure of clay minerals and cements are important factors that cause strong sensitivity of reservoir. It is suggested that the compatibility between working fluid and formation fluid should be done well in drilling and completion, and the injection production flow rate should be controlled under formation conditions to avoid reservoir damage.