Abstract: This paper brings forward a new concept of design for aggregate gradation of OGFC mixture in which gradations are designed according to different roles of fine and course aggregates in the mixture.A new design method of course aggregate gradation of OGFC mixture is proposed based on discrete element method and experimentation.The passing rate of sieve of 4.75 mm is recommended as the control point of course aggregate graded design.First,based on theory of discrete element method,optimum volume percentage of various particle diameters of course aggregate is calculated.Second,the VCA_min is verified on the basis of the single factor dry rodded test of coarse aggregate.Finally,course aggregate gradation was determined according to the requirements of air void of course aggregate and designed air void.The N method is adapted to design the fine aggregate gradation.To meet the requirements of designed air void,the content of 2.36-4.75 mm must not exceed 5%.The new grade range of OGFC mixture is also presented.