Through the study of packing and filling characteristics of aggregate, the dosages of coarse and fine aggregate and filling were calculated for aggregate of skeleton denseness asphalt mixture. According to the packing theory and the fractal theory, the mathematical models of coarse and fine aggregate gradation design were presented in terms of the different frame effects and filling actions of coarse and fine aggregate. The formulae of coarse aggregate adjustable gradation design were put forward. Three groups of the mineral gradations of asphalts mixtures were got by these equations. Results show that the coarse aggregate is 74%; the fine aggregate is 15.20% and the filler is 10.8% in skeleton denseness asphalt mixture; the volume parameters of three gradations, flow value and dynamic stability of three groups of asphalt mixtures all meet the needs of technical specification.