On the basis of tests and statistics analysis,influence of proportion of coarse/fine aggregate contents on the gradation and volume parameters were investigated,and then the main difference and influencing factors of volume parameters and designed asphalt content between coarse/fine gradation mixes were further studied.The results show that though the coarse/fine aggregate contents have significant effects on gradations only volume structure of fine aggregate affects the asphalt mixed of continuous gradation;when the condition of designed air voids are equal,voids in the mineral aggregates and designed asphalt content of asphalt mixes with coarse gradation are higher than that with fine gradation,when the coarse aggregate contents don't exceed about seventy percent,asphalt mixes appear suspension-dense structures.