Abstract：Prescriptions，Chinese medicine，and clauses about diarrhea caused by greater yang disease in Shanghan Lun were sorted out and analyzed. Parthenogenesis and main symptoms of each category of diarrhea，as well as the main points of identification for prescriptions and Chinese medicine，were clarified so as to precisely know the condition in which each prescription is advisable. The following decoctions were involved in the prescriptions， Chinese medicine， and clauses： Gegen tang， Gegen plus Banxia tang， Gegen Qinlian tang， Xiaoqinglong tang， Shengjiang Xiexin tang， Gancao Xiexin tang，Chishizhi Yuyuliang tang，Guizhi Renshen tang，Huangqin tang，Huangqin plus Banxia Shengjiang tang. Based on tang as the principle as well as prescriptions，Chinese medicine，and clauses as the entry，a careful and detailed analysis was made. After the analysis，the results were as follows：the diarrhea treated with Gegen plus Banxia tang is caused by Gegen tang syndrome complicated with fluid retention stagnating in the interior； the diarrhea treated with Gegen Qinlian tang is caused by yin deficiency with internal heat， accompanying the main symptoms including faint and rapid pulse， dyspnea， fever，and sweating；the diarrhea treated with Xiaoqinglong tang is induced by the failure of exterior pathogen to release and the internal stagnation of fluid- dampness， accompanied with the main symptoms， such as floating and tight pulse， the severity of aversion to cold greater than that of fever，cough，and vomiting；the diarrhea treated with Shengjiang Xiexin tang was induced by water failing to transform into qi and yin-yang deficiency，with sunken and weak pulse；the diarrhea treated with Gancao Xiexin tang is induced by deficiency cold of the middle energizer and the disorder of water transportation and transformation， with sunken and weak pulse； the diarrhea treated with Chishizhi Yuyuliang tang is caused by intestinal dampness heat，mainly manifested by burning sensation of the anus and stool containing pus and blood；the diarrhea treated with Guizhi Renshen tang is induced by the failure of exterior syndrome to release and yang deficiency of the middle energizer，marked by floating and weak pulse，thirst，and cold hands and feet；(8)the diarrhea treated with Huangqin tang is caused by pathogen entering lesser yang， marked by weak and string- like pulse， and abdominal pain complicated with muscle spasm in the abdomen.