Abstract: The mechanical model of crack closure was established, and the zone of crack closure was calculated combining with the abutment pressure formula. The crack closure evolution in the abutment pressure area was analyzed, based on which the rule of permeability evolution in the abutment pressure zone was obtained. The results show that: in the abutment pressure area, when the original stress is bigger than a certain value, the cracks experience the process of “completely closed - partially open - fully open” and permeability undergoes a process of “slow increase-rapid increase-sudden increase”; when the original stress is smaller than a certain value, the cracks experience the process of “fully open-partially closed-completely open” and permeability undergoes a process of “slow increase-decrease-sudden increase”. In the end, the numerical software of comsol was used to simulate the permeability evolution in the abutment pressure area and the result was consistent with the theoretical analysis.