The thickened surplus sludge from municipal wastewater treatment plants is generally mechanically dewatered after regulated with flocculants and the type and dosage of flocculants will influence the dewatering effect directly.And the cost of flocculants is the main part of operating cost of sewage sludge treatment.With the processing practice on yields,thickening and dewatering pattern of Zhenjiang Wastewater Treatment Plant,the analysis and selection of flocculants are carried out with respect to the type and dosage of flocculants for sewage sludge regulation.the principles for flocculants selection and simple calculation method for chemicals cost for sludge treatment are proposed.It is suggested that the dosage of flocculants for sludge regulation should be adjusted in different seasons in real operation of the municipal wastewater treatment plants.