Abstract： This paper introduces Professor CAO Yi's clinical experience in using Haoqin Qingdan Decoction to treat eczema of damp-heat accumulation type. According to the climatic characteristics of Jiangsu and Zhejiang provinces and the dietary habits of the residents，Professor CAO Yi believed that the etiology of eczema of damp-heat accumulation type is pathogenic factors of dampness and heat throughout the disease course. The core pathogenesis is the inhibited qi movement of the triple energizers， disturbance of shaoyang pivot movement，gallbladder-heat attacking the lung and damp-heat obstructing in the middle energizer. In terms of compatibility，Haoqin Qingtan Decoction has the effects of clearing and venting，diffusing the upper energizer，freeing the middle energizer and draining the lower energizer，and thus the method of dispersing pathogens separately and discharging can be applied to harmonize shaoyang. When applying Haoqin Qingdan Decoction to treat eczema，it is necessary to grasp the following symptoms as the main points：red skin lesions，exudation，pruritus，bitter taste in the mouth，red tongue，greasy coating and wiry pulse. Due to the decoction is cold and cool in its nature，attention should be paid to the care of the spleen and stomach when it is used. Therefore，when Professor CAO Yi differentiates to treat eczema of damp-heat accumulation type，he emphasizes on promoting the triple energizers，freeing the activity of shaoyang，soothing the liver and rectifying the spleen，and simultaneously treating the liver and spleen.