Abstract: In view of the characteristics of Chang 2 reservoir of northern part of Beigou in Xiasiwan oilfield, Chang 2 reservoir sensitivity analysis has been carried out. The results show the reservoir is not sensitive to fluid velocity, with weak velocity sensitivity. Water sensitivity is medium to weak. Weak salt sensitivity has no critical salinity. Acid sensitivity is medium and alkaline sensitivity is weaker. The 5 kinds of reservoir sensitivity is relatively weak, which has little effect on water flooding of the study area. However, because of high content of chlotite, the acidify is inadequately applied in the research area.