As the need of the current construction of green economical society , its in urgent need of developing green concrete material , to extend the durability of building structures .Through experiment , it designed three dif-ferent strength grade of concrete , and comparative study of different dosage of the ultra-fine fly ash, in 28 days and under a long age as 60 days and 90 days, the regular pattern of compressive , tensile and flexural strength , it is concluded that the best dosage is 20%, its compressive strength , tensile and flexural strength , the strength of 90 d, than the 28 d benchmark increases by about 16.5%, 16.8%and 15.2%, compared with ordinary concrete is in-crease 10.6%, 5.5%and 8.1%, increased by 5%~10%or so, it showed that the ultra-fine fly ash concrete ex-perienced for a long period of time after curing , it has more fully hydration reaction , the strength still has large im-provement , it meet the requirements of normal use , and can effective to save cement , improve the durability of the materials for popularization and application value .%随着当前建设环保节约型社会的需要，急需发展绿色混凝土材料，延长建筑结构的耐久性。通过试验的方法，设计了三种不同强度标号的混凝土，对比研究不同掺量的超细粉煤灰，在28天、60天及90天的较长龄期下，其抗压、抗拉及抗折强度的变化规律，结果表明：最佳掺量为20％，其抗压、抗拉及抗折强度，在90 d时比28 d基准强度提高约16．5％、16．8％和15．2％，相比于普通混凝土本身增长幅度的10．6％、5．5％及8．1％，提高5％～10％左右，说明超细粉煤灰混凝土在经历长时间的养护后，水化反应愈加充分，对强度仍有较大的提升，既能满足正常使用的要求，又能够有效节约水泥，提高材料的耐久性，具有推广和应用价值。
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