Abstract: Flocculation is used to change distribution of suspended particles size.Hydraulic conditions created by flocculation reactor play an important role in the distribution of three-dimensional flow field,and it has decisive effect on floc growth and particle size distribution.PAC coagulant was prepared,suspended particles in Kaolin water solution were selected as objects for removal.Online instruments including turbidimeter and particle counter were used to monitor the flocculation process online and collect test data.The tests were to study the distribution characteristics of suspended particles in flocculation process.Simulation of three-dimensional flow field of the flocculating reactor was also conducted at various flocculation conditions.The results can be used to improve the distribution of turbulent flow in the reactor and delivere good flocculation effect.