A native polysaccharides (RRP) was isolated from Ra dix Rehmanniae Preparata by microwave-assisted extr action (MAE). In the method, the optimized conditions were : the ratio of raw material to water was 1:50 (g/ml ); microwave irradiation power was 550W; extraction temperature was 60 °C ; extraction time was 30min. As a result, the avera ge yield of RRP using MAE was 9.35%, and R.S.D. was 2. 15%. Furthermore, RRP which was extracted by MAE an d was purified (RRP MAE ) and (PRP HWE ), PRP HWE can stimulate the proliferation and differentiation of osteoblasts in vitro