Abstract: treatment of coal slurry water is a long-standing issue that is difficult to cope with in coal preparation plants. Following an introduction to the physiochemical property of coal slurry water, an analysis is made in the paper of the main factors and mechanisms affecting flocculating settling of particles in coal slurry water. The measures for improving the settling efficiency of particles and the points requiring attention are pointed out. The author also puts forward suggestions and points out the direction for improvement in making analysis and treatment of coal slurry water.