A kind of simple aqueous two-phase system composed of acetone,inorganic salt and water was used to separate and purify carthamine from safflower petals.Experimental results show that(NH4)2SO4 has the stronger phases-forming ability than K2HPO4 and NaCl.The optimum conditions for isolating carthamine from safflower yellow were chose as V(CH3)2CO=5mL,VH2O=5mL,m(NH4)2SO4=2.5g.Under the conditions,the yield can reach to 99 % for the extraction of carthamine with the partition coefficient K>55.The carthamine product with high purity was obtained using analog counter-current extracting experiment.