Discoloration of Yunnan Hemlock lumber during drying is a major problem that caused degradation of lumber. In this article, the reasons causing discoloration were analysed based on the research results and practical experience. A suitable drying schedule and some measures for reducing discoloration ratio of Hemlock lumber were also suggested. According to the suggested drying schedule, the discoloration ratio of Hemlock lumber could be cut down to 10% and quality of the lumber could meet corresponding national standard.