Research on the treatment efficiency and coagulation experiments was done using a new compound flocculation agent SE in printing and dyeing wastewater. Taking COD and chromaticity color as indexes, We did research on the coagulation efficiency under different condition of SE dosage, pH value, settling time, and agitation speed, and then we did comparative experiments between SE and PAC, SE and PFS. The experiments show that SE can effectively remove COD and chromaticity color. The four parameters namely pH of 8 - 10, settling of 30 min, agitation of 75 r/min and dosage of 155 mg/L were chosen, the COD and chromaticity color removal rate were recorded as high as 83% and 94% respectively, and the optimum effluent COD and chromaticity color were 155 mg/L and 37 respectively. Compared with PAC and PFS, SE produced bigger and more compact floc, settling time was shorter, the amount of mud and chemical dosage were less, and effluent quality was much better. The results show that SE is a high-effective and practical compound coagulant agent.