Currently, most low permeability reservoirs are developing by water flooding; its development effect becomes worse when the water cut reaches a high period at the later stage of water flooding development. In this situation, the CO₂ flooding development method becomes a more effective method of enhanced oil recovery. The major difference between CO₂ injection and other gas injections is that CO₂ has a much higher solubility in water. Therefore, CO₂ solubility in water cannot be ignored in CO₂ flooding, especially after water flooding when water saturation has increased significantly. In this article, some five-spot well group numerical compositional mechanism models were built based on the basic geological and fluid parameters of a low permeability reservoir in Xinjiang Oilfield. The numerical simulation of CO₂ flooding was applied to analyze the influence on the enhanced oil recovery, CO₂ breakthrough time, and geological sequestration of different factors, including salinities, water saturation, gravity effect, and plane heterogeneity.