CO2 flooding and horizontal well development technology have a good effect on enhancing oil recovery in low permeability reservoirs, but for low permeability reservoirs with strong heterogeneity, there is a problem of low production degree after water flooding development. Therefore, it is necessary to study the injection-production mode and the adjustment and optimization of injection-production well pattern in late stage of low permeability reservoirs and the influencing factors of development effect. Firstly, a heterogeneous conceptual geological model is established according to the target reservoir, and a reservoir model with low permeability and high permeability is established. Reservoir numerical simulation method is used to simulate the reservoir. After water flooding for a period of time in the reservoir model, the infilling and adjusting well pattern adopts CO2 injection in horizontal Wells to carry out secondary water and gas co-flooding. By comparing the recovery degree and formation pressure of different infill pattern patterns, the optimal infill pattern was obtained for secondary optimization development. Then, based on the optimal well pattern optimization and adjustment model, the effects of well spacing, reservoir permeability and CO2 injection pressure on the development effect of the adjusted well pattern were studied. Numerical simulation of reservoir shows that infill horizontal well is better than infill vertical well. Infused horizontal well gas injection can shorten the row spacing properly, so that CO2 displacement is more sufficient. When the well spacing/row spacing is 0.4, the recovery degree is the largest. Under different reservoir permeability conditions, the horizontal well can be placed along the direction of low horizontal permeability when the well pattern of horizontal Wells is encrypted under the same production conditions. Properly increasing the injection pressure of gas injection well can effectively improve the recovery of formation energy. The research results of this paper have a good reference for the development of such heterogeneous low permeability reservoirs.