The invention belongs to the technical field of evaluation for gas storages of gas fields, and particularly relates to an evaluating method for a closure property of a lithologic gas reservoir type gas storage. The evaluating method comprises the steps that evaluation of the closure property of a cover plate and a bottom plate is performed, specifically, the macroscopic closure property of the cover plate and the bottom plate is evaluated firstly, and then the microscopic closure property of the cover plate and the bottom plate is evaluated; the evaluation of the closure property of a lateralboundary is performed, specifically, the microscopic closure property of the lateral boundary is evaluated firstly, then a spatial form of the lateral boundary is evaluated, and finally dynamic evaluation of the lateral boundary is performed; and the overall sealing capability of the gas storage is inspected. According to the evaluating method for the closure property of the lithologic gas reservoir type gas storage, the problem that no systematic evaluating method for the sealing capability of the lithologic gas reservoir type gas storage is obtained in the prior art is solved; and the evaluating method is scientific, reliable, and highly operable on site, the sealing property of the gas storage is more accurately judged, the problem that the closure property of the lithologic gas reservoir type gas storage is difficult to demonstrate due to the trapped boundary is solved, the construction risk and the operational risk of the gas storage are reduced, and the safety of the gas storageis improved.