With the rapid development of urban construction, the waste that construction brings is also increasing. The recycled concrete technology can solve the problems of waste concrete, but also save the natural sand. This paper gives the progress on the research about the reliability of recycled concrete. Because of the rough surface of the recycled concrete aggregates and large porosity, the apparent density, strength and durability of the recycled concrete are different from the ordinary concrete on many aspects. So the study of the reliability about the recycled concrete is very necessary. The page will research on the material subentry coefficient of fifty and sixty years.