This study is to investigate experimentally the effect of the use of recycled aggregate powder(RP) on the properties of mortar using recycled fine aggregates(RA) and blast furnace slag powder(BS) without portland cement. The results can be summarized as follows : For the fresh mortar, an increase in RP contents leads to increase W/B, Air contents increase gradually below 100 % of RP contents. As the RP contents increase, the compressive strength decrease gradually. Besides, as the RP contents increase, the strength deviation with curing temperature is negligible at 91 days, compressive strength at $20^{circ}C$ was higher than that at $35^{circ}C$. The flexural strength show a similar trend to the compressive strength in general, and the ratio of compressive strength to flexural strength is distributed within 1/1 ~ 1/3 in general, which is higher than the range of ordinary concrete. Meanwhile, as a result estimation of strength development, as the RP contents increase, the strength development trend is weakened gradually, but elapse with age, in case of RP 25 % show that strength level has similar with BS 100 %. It is thought that substition of RP for BS will be available for securing quality improvement within 25 %.