A novel flocculant (CATCS) based on corn starch and chitosan was prepared and its flocculation behaviors were studied. The synthesis conditions of CATCS were discussed and the production obtained was characterized using Fourier infrared spectra and scanning electron microscopy. Flocculation properties of the products were evaluated in terms of transmittance, removal of organic contaminant and solid suspending substances. Influences of temperature, pH and flocculant dosage on flocculation efficiency of CATCS were examined. CATCS had better flocculation performance at lower temperature for the wastewater investigated. CATCS showed better flocculation performance than cationic starch and chitosan in 5 g/L kaolin suspension trended to performance well in acidic and alkaline solution. The comparison of the flocculation performance between CATCS, Fe-2(SO4)(3) and polyacrylamide showed CATCS had much efficient flocculation performance. In addition, cationic starch was prepared from corn starch using microwave-assisted method. (C) 2009 Elsevier B.V. All rights reserved.