In order to investigate the effect of proportion of buton rock asphalt on the performance of modified asphalt mixture with wet method，Penetration 70 Grade A petroleum asphalt was used as base asphalt for preparing the modified asphalt binder containing rock asphalt up to 40% of the base asphalt. Limestone aggregate was used in designing the AC-20C asphalt mixture of various percentages of rock asphalt by using Marshall method. Laboratory tests were carried out to determine the properties of the asphalt mixture modified with Buton rock asphalt. These properties include dynamic stability from rutting test， retained Marshall stability from immersion Marshall test， tensile strength ratio from freeze-thaw indirect tension test， failure strain from low temperature flexural test， water permeability coefficient from permeability test， compressive resilient moduli from compression tests at 20 ℃ and 15 ℃， and tensile strength from indirect tension test at 15 ℃. The test results and analyses indicate that with the increase of rock asphalt percentage，the high temperature rutting resistance， moisture damage resistance，permeability resistance，stiffness， and strength of the modified asphalt mixture improve gradually to varying degrees.On the other hand，with the increase of rock asphalt percentage，the low temperature cracking resistance of the modified asphalt mixture improves to a peak value and then falls back slightly.The recommended maximum percentage of Buton rock asphalt for paving asphalt mixture is 30% of the base asphalt.