CO₂ could react with formation water and reservoir rock when it was injected into reservoir. The interaction of CO₂-rock-water could change the porosity，permeability and pore structure characters of the reservoir. In this paper，the changes of porosity，permeability and pore structure of the rock were measured after rock reacted with CO₂ and water in different reaction times and under different reaction pressures. The apparent morphology of the rock and Ca²⁺ concentration in water after the interaction of CO₂-rock-water under different pressures were also measured. The results showed that the change in pore structure of rock was influenced by the comprehensive effects of dissolution，particle migration and the deposition of new minerals. With the change of reaction time and reaction pressure，the distribution of small pores in rock changed greatly，while that of macropores changed little.The water permeability of rocks all decreased after CO₂-water-rock reaction of 6—24 hrs. With the increase of reaction time，the porosity of rock decreased first and then increased，the permeability recovery of rock increased gradually which showed that the effect of CO₂ on reservoir permeability changes decreased gradually. The water permeability of rocks all decreased after CO₂-water-rock reaction under 7—15 MPa. With the increase of reaction pressure，the porosity of rock increased first and then decreased，the permeability recovery of rock decreased gradually which showed that the effect of CO₂ on reservoir permeability changes increased gradually. The dissolution of rock was more obvious and the concentration of Ca²⁺ in solution increased with the increase of reaction pressure.