Based on the mechanism analysis of reservoir sensitivity, the relationship between sedimentary microfacies and reservoir sensitivity is studied, and the spatial distribution of reservoir sensitivity is revealed. The main oil-bearing formations are member 2 and member 3 of the in Shahejie group in Oligocene series in Linnan oilfield, Linnan depression, Huimin Sag, Jiyang downward in Bohai Bay basin, whose sedimentary facies is delta. Because of the different petrography in different sedimentary microfacies, there is different reservoir sensitivity. Generally, the sedimentary microfacies that have fine grains, such as bank and crevasse splay, have much more clay mines than the sedimentary microfacies that have coarse grains, such as under-water branched channel and debouch bar. So the former has stronger reservoir sensitivity than the latter in water sensitivity, flowing velocity sensitivity and acid sensitivity. Compared with delta plain, delta front has weaker water sensitivity, flowing velocity sensitivity and acid sensitivity. On the basis of the above study, we can predict the spatial distribution of reservoir sensitivity according to the sedimentary microfacies, and then design program to protect oil-bearing reservoirs. Based on the mechanism analysis of reservoir sensitivity, the relationship between sedimentary microfacies and reservoir sensitivity is studied, and the spatial distribution of reservoir sensitivity is revealed. The main oil-bearing formations are member 2 and member 3 of the in Shahejie group in Oligocene series in Linnan oilfield, Linnan depression, Huimin Sag, Jiyang downward in Bohai Bay basin, whose sedimentary facies is delta. Because of the different petrography in different sedimentary microfacies, there is different reservoir sensitivity. Generally, the sedimentary microfacies that have fine grains, such as as the bank and crevasse splay, have much more clay mines than the sedimentary microfacies that have coarse grains, such as under-water branched channel and debouch bar. So the former has stronger reservoir sensitivity than the latter in water sensitivity, flowing velocity sensitivity and acid sensitivity. Compared with delta plain, delta front has weaker water sensitivity, flowin g velocity sensitivity and acid sensitivity. On the basis of the above study, we can predict the spatial distribution of reservoir sensitivity according to the sedimentary microfacies, and then design program to protect oil-bearing reservoirs.