<p>The oil recovery of Lianchi tight oil reservoir Da’an Zhai section was lowly and development was difficult, then carried out the numerical simulation study of CO₂ injection in Lianchi tight oil reservoir. Established the CO₂ development numerical model of Lianchi oilfield (double pore model and compositional model) through combined the reservoir characteristics of Lianchi oilfield and fluid properties. Respectively predicted the increasing oil effect of three injection-production methods with displacement mode, CO₂ huff and puff, cyclic huff and puff mode. Evaluated the development effect on the basis of CO₂ oil draining rate and the increment of oil recovery. The results showed that, the development effect of cyclic huff and puff mode was best in three kinds of gas injection modes, the best time of well shut in was 3 months, the injection-production cycle of CO₂ cyclic huff and puff was 4 years. At the same time, the optimal scheme of the gas injection was determined through comparative research, which provided the technical reference for the development of Lianchi oilfield for injection CO₂.</p>