According to the geological characteristics of Gulong South area, the quantitative analysis of the effect of capillary force on improving oil recovery in G block asynchronous injection-production is studied. The effect of capillary force in the process of asynchronous injection and production is analyzed by establishing 3D geological model, numerical model and historical fitting. The results show that: Using block G to complete the quantitative characteristics of asynchronous and synchronous injection-production capillary force, it is calculated that when the wetting Angle is 60 degrees and the capillary force is 0.3 MPa, the capillary force is 0.01 MPa-3 MPa, and the pore throat radius ranges from 0.17um to 51.96um, the pore throat radius ranges from 0.9um to 1.3um and the frequency is higher. The correlation between throat radius and permeability is the best, and the asynchronous injection recovery degree is the highest (12.27%). Under the same wetting Angle and capillary force, the recovery degree of synchronous injection is 11.09%, and the recovery degree of asynchronous injection is 1.18% higher than that of synchronous injection. The research results have a significant effect on the actual development of G block in an oilfield.