A natural macromolecular cationic flocculant(NMCF) was achieved from corn-core powder by chemical modification.We studied its Floccualating performance using turbid kaolin and kieselguhr solution. The experiments show that NMCF has optimal dosage and pH value for flocculation and its performance is superior to that of inorganic coagulant(AC) and PAM which is made in China.