This paper introduces the method of how to improve superfine sand grading and fineness modulus by the use of crushed_run stone which contains 20 percent of stone chippings smaller than 5 mm,and the technical means of how to formulate superfine_sand high_strength concrete(HSC) by blending fly_ash and admixture.In addition,based on the analysis of the results obtained from numerous comparative experiments on factors influencing concrete strength,the parameters of mix proportion for C50 and C60 superfine_sand HSC are determined.