Abstract: The clastic reservoirs in Tahe oilfield have the characteristics of low permeability, poor physical property and strong heterogeneity. The reservoir is difficult to be reformed. In this paper, the core composition and clay content of the core were analyzed by thin-plate identification, x-ray diffraction, and scanning electron microscopy. The sensitivity of the core layer of the clastic rocks in Tahe oilfield was tested by core flow experiment. The experimental results show that the reservoir clastic rocks have strong alkali sensitivity, medium and strong water sensitivity, medium weak salt sensitivity, weak speed sensitive, no acid sensitivity, and the mechanism of sensitive injury was analyzed. It is advisable to keep the injection rate below the critical flow rate when injecting fluid into the reservoir. Attention should also be given to preventing the alkaline solution from penetrating into the formation to prevent precipitation, clogging the throat and damaging the reservoir.