Abstract: The Changtai company′s coal preparation plant is irrational in design. To address this problem, the scheme for remolding the washing process of the plant is defined based on the result of analysis of the causes and the property of raw coal. After implementation of the renovation schemes, the washing system has reached the designed capacity and the ash, moisture and sulfur of clean coal are well up to the requirement in quality for injection in blast furnace, and the middings product with a calorific value of 14.65 MJ/kg can be sold as power coal. Furthermore, the renovation has led to reduced loss of clean coal in middlings, reduced calorific value of middlings and noticeably improved raw coal separation result.