There are problems of high injection pressure and low recovery in the process of tight oil reservoir displacement. This paper proposes to apply olefin ester oil displacement agents to the displacement development of tight oil reservoirs. In this paper, taking 9-decene acid methyl ester as an example, through tight core flooding experiments, the advantages of the injection pressure and oil displacement effect of olefin ester flooding agents over conventional oil flooding agents in the process of tight core flooding are studied. Methyl 9-decenate is insoluble in water and can be miscible with organic solvents such as ethanol, ether, acetic acid, etc., and can rapidly transfer mass to the depth of the core during the displacement process. The research results show that for the 0.5mD tight core, the displacement pressure of methyl 9-decanoate is greatly reduced compared to conventional oil displacement agents, which is less than 1/30 of the water flooding pressure, which is suitable for the flooding of tight oil reservoirs. For development. Injection pressure of oil-displacing agent: deionized water> rent reducer> nano solution> 9-decene methyl ester. At the same time, the flooding experiment showed that, by injecting 2PV9-decanoate methyl ester first and then water flooding, the recovery degree of 9-decanoate methyl ester flooding reached more than 80%, and the comprehensive recovery degree reached more than 90%. After water flooding, 0.3PV and 1.5PV9-methyl decanoate slugs were injected to increase oil recovery to 20.61% and 57.52% respectively. Ester oil-displacing agents have good injection adaptability in the development and application of tight oil reservoirs, and at the same time can greatly improve the degree of recovery, and have broad application prospects.