The formation of Schiff base (B-CTS) by chitosan and benzaldehyde protects the amino group of chitosan,and then B-CTS reacted with succinic anhydride to synthesize succinyl chitosan(SACTS).The structure and morphology of SACTS were characterized by FTIR, 1HNMR, XRD and ESEM.The effects of the amount of acid acceptor, the amount of succinic anhydride, the reaction time and the reaction temperature on the carboxyl content and esterification rate of SACTS were discussed.The results showed that the optimum conditions were as follows: m (B-CTS): m (triethylamine) = 1: 4,dosage of succinic anhydride was m (B-CTS): m (SAA) = 1: 5, The reaction time was 6.5 h and the reaction temperature was 65 ℃.Under this process conditions,The carboxyl content and esterification rate of SACTS were 93.01% and 71.13%, respectively.The flocculation experiment was carried out with SACTS and the prepared pheromone dye wastewater,The effects of pH, initial turbidity and temperature on flocculation were investigated.The results showed that when the flocculation conditions were pH = 1 ~ 4, the dosage was 1 ~ 10mg / L, the initial turbidity was 200 ~ 800NTU, the temperature was 20 ~ 30 ℃, the turbidity removal rate of supernatant was More than 95%, pyrotenine dye residual rate of 10% or less.The zeta potential of the supernatant and the XPS spectra of the flocculation showed that the flocculation process of SACTS and Pyrobinum wastewater was achieved by the interaction between the neutralization and the adsorption bridging.