Abstract: Coal slurry water treatment process is a crucial link in coal washing operations. The problems facing Buertai Coal Preparation Plant are high proportion of fine slime in thickening system, instability of property coal slime, inconsistency of quality of overflow of thickener due to delay in making adjustment with agent, and high consumption of agent. Through upgrading of the plant′s existing agent dosing system with the use of a slurry water double-monitoring system and an online slime-water interface detector, an online slurry water thickening monitoring and control system is developed. The upgrading work has led to reductions of consumption of aluminium polycholoride(PAD) and polyacrylamide(PAM) by respectively 0.78 g/t and 2.27 g/t, a rise of thickening efficiency by 0.77%, ease of labor intensity and realization of a benign slurry water circulation system, laying a foundation for the intelligent development of the plant.