The polysaccharide APS-3c was isolated from Angelica sinensis(Oliv.) Diels through water extraction,deprotein,ethanol precipitation,and DEAE-column chromatography respectively,and was further purified by Sephacryl S-400 and Sephadex G-100 column chromatography.The phenol-sulfuric acid assay,carbazole method and Bradford method were used to determine the contents of carbohydrate,galacturonic acid and protein,respectively.The molecular weight was carried out with high-performance size exclusion chromatography (HPSEC) combined with a differential refractometer detector.The monosaccharide compositions were determined by gas chromatography after complete hydrolysis with acid.The HPSEC result showed that the APS-3c was a single homogeneous component and its molecular weight was 1.4×104 Da.The monosaccharide composition of APS-3c was arabinose,rhamnose,glucose,galactose,mannose,xylose,galacturonic acid.The results of the MTT assay indicated that APS-3c inhibited the proliferation of human myeloblastic leukemia HL-60 cells in a concentration-dependent manner.The inhibition rate of 10 mg/L APS-3c on human colon carcinoma SW1116 cells was 35.1%.