To study the effect of continuous gradation of recycled coarse aggregate(RCA) on the concrete properties, the optimum mixture mass ratio(MMR) between two kinds of single grain class of 160315mm and 50200mm, while reaching the state of the maximum packing density(MPD), was finally determined by means of measuring maximum packing density, water absorption and sieving analysis of continuous gradation RCA as well as the slump of the fresh concrete and the compressive strength of the hardened concrete at the ages of 7d, 28d and 60d. The experimental results show that both the MPD and water absorption of the continuous gradation of the RCA all appear a trend of early increase and late decrease along with the gradual decrease of the MMR between two kinds of single grain class of 160315mm and 50200mm, but the fluctuations of these values are not big. The influences of different continuous gradation RCA on the workability of the fresh concrete are very remarkable with the increase of the mass proportion of the 50200mm single grain class, and the effect on the compressive strength of the hardened concrete is also very significant. Both of them are all shown a trend of early increase and late decrease. The optimum MMR between 160315mm and 50200mm of single grain class of the RCA is 70∶30.