To reveal the influence of overpressure on hydrocarbon migration and accumulation in Linnan Subsag and clarify its control on hydrocarbon enrichment，we restored the dynamic evolution of the paleo-pressure field based on the static pressure field tracking geological blocks and analyzed the relationship of overpressure with hydrocarbon migration and accumulation. The results reveal that the pressure field of Linnan Subsag presents as atmospheric pressure，weak overpressure，and overpressure in the zones of uplift，slope，and subsag，respectively. The overpressure of Es3 is evident，followed by that of Es4. The overpressure evolves in a cycle of early low amplitude pressurization（the depositional periods of Es1-Ed），uplift pressure relief（the depositional periods of Ed）and late rapid pressurization（the depositional periods of Ng-Q）. Now it is in the most distinct stage of overpressure，and the overpressure center is located in the sedimentary center of subsag. A comprehensive analysis of hydrocarbon migration and accumulation clarifies that the abnormal high pressure in the Es3 in Linnan subsag contains the generation and migration of oil and gas. During the deposition period from Guantao Formation to Minghuazhen Formation，the rapid increase in oil potential dominates the migration directions and favorable accumulation positions of oil and gas.