Abstract: Facfors influencing the thickness of pulp layer stuck on a steel ball in wet grinding mill are analyled in this paper.Results of research showed that the thickness of pulp layer stuck on a steel ball increases with the growth of volumetric density of pulp,and there is a critical point of about 50% for solids content.When the pulp density is over the critical point,the layer thickness increases rapidly.The thickness increases with growth of Blaine index of ore particle,and the higher the pulp density is,the more the thickness increases.Adding of chemicals can improve the rheological behavior of high density pulp,thus improving the performance of grinding.Under the condition that pulp property is constant,the speed of pulp flowing has no influence on the thickness of pulp layer stuck on a steel ball.