The invention provides an oil displacement method of injecting strong high pressure air into deep ancient buried hill reservior and enriching oxygen which comprises the following steps that first, high-pressure gas-injection well completion is performed to a gas-injection well, 0.05-0.15PV initiating agent which comprises sodium sarcosinate and mannitol is injected into the gas-injection well after well completion; strong high pressure gas injection is performed, 30000-50000 standard cubic air is injected into the formation; by removing nitrogen from the air, oxygen-enriched gas mixture containing 50-70% of oxygen by mass is separated, and the oxygen-enriched gas mixture is injected into the oil reservoir; strong high pressure gas injection is performed; when the formation cracking is stable, the gas injection is increased for strong high pressure gas injection. According to the oil displacement method of injecting strong high pressure air into deep ancient buried hill reservior and enriching oxygen, the original colloid and heavy crude oil is cracked under the action of the formation temperature by strong oxidation, the oil-producing rate and the oil-recovery rate of the subsequent air flooding are enhanced greatly, the oxidative cracking reaction time is reduced, rapid oxidative cracking is achieved and the service efficiency of the gas is improved.