Abstract: In this paper the influence of turbulence on sediment coagulation is studied. The author discusses some theories of flocculation dynamics presented in many researches about wastewater treatment.and thinks that these theories fit to research of sediment coagulation. Based on the test of fine sand and compared with othors,the result shows that there are two periods in fines flocculation in turbulent flow in which the influence of trubulence on the flocculation is different.