Injection-production disturbance will lead to varying degrees of elastic-plastic deformation of micro-pore structure of carbonate gas storage caprock, and even macro damage of the cap rock, resulting in cap rock leakage. According to the characteristics of high-speed reciprocating injection-production in gas storage, the dynamic sealing evaluation of caprock under injection-production conditions was carried out from geological features, capillary physical sealing and macro mechanical integrity. Taking the carbonate caprock of Q gas storage as the background, the influence of alternating mechanics on the dynamic sealing of caprock was clarified through the dynamic sealing test under injection-production conditions. It was found that under alternating load, the permeability and breakthrough pressure showed the trend of first decline-stability-rise. When the confining pressure was large, the law is mainly in the decline-stability stage; Through the stress-strain curve and acoustic emission characteristics, the fatigue failure risk and acoustic emission signal characteristics of caprock were defined, which showed that the alternating fatigue failure risk was low under injection-production conditions; Using AHP and extension theory comprehensively, the dynamic sealing of carbonate gas reservoir cap was evaluated. Q gas reservoir cap is evaluated as excellent dynamic sealing. The establishment of the evaluation system provides a scientific basis for the dynamic sealing evaluation of carbonate gas reservoir caprock.