Abstract: Taking the Biqian 57 wellblock with highly developed faults in Xinzhuang oilfield of Henan oil region as an example, sealing abilities of the faults are quantitatively analyzed by using the configuration of formation, lateral sealing coefficient of fault and smear factor of mudstone as the appraisal parameters. The calculation results are in accordance with the areal distribution of oil and gas. This method can be used to study the sealing ability of regional faults.