The basic property information of rock asphalt was obtained through the tests of asphalt properties, infrared spectrum, element analysis and solubility analysis. The characteristic of high softening point, an analysis method of using standard curve to deduce the softening point were established. The O-Si-O and carbonate carbonyl C=O in the rock asphalt were strengthened and closely related to the molecular force of asphalt. The arrangement structure of asphalt macromolecules was changed, which makes asphalt have stronger cohesion. The content of ring structure is more and the chain structure is less. The asphalt system have high stability due to the structural composition. The dissolution state shows that there are more inorganic minerals and some amorphous insoluble substances in rock asphalt, which can significantly improve the softening point of modified asphalt. The rock asphalt can be used as an excellent natural modifier to significantly improve the comprehensive properties of modified asphalt.