In order to reveal the mechanism that carbon dioxide dissolved in heavy oil in the presence of solubilizer，the solubility of carbon dioxide in heavy oil was experimentally determined as a function of temperature，pressure and the content of solubilizer 1，2-dimethoxyethane. The solubility parameters of carbon dioxide under different conditions were calculated by molecular dynamics simulations. The radical distribution functions of carbon dioxide and solubilizer were calculated. It was found that lower temperature，higher pressure and greater content of solubilizer are favorite to the dissolution of carbon dioxide，in accordance with that found in experiments. It is the strong attraction between carbon dioxide and 1，2-dimethoxyethane molecules that led to the solubilization of carbon dioxide in heavy oil. The results provide a theoretical direction to development of solubilizers of carbon dioxide in heavy oil. Those small organic molecules rich in ether groups are potential solubilizers of carbon dioxide.