Background:Prediabetes is a growing health concern,a large percentage of whom will develop full 2 type diabetes. The prominent symptom of patients with diabetes and prediabete is fatigue.The syndrome of spleen-deficiency phlegm-dampbess is the main syndrome of prediabetes.Effective intercentions on prediabetes will delay or prevent the occurrence or development of diabetes. Methods:Randomized controlled trial is implemented in this study.The study term is 3 months.Participants are recruited from Binhai hospital of Tianjin of Traditional Chinese Medicine,Jinghai hospital of Tianjin of Traditional Chinese Medicine and affiliated Wuqing hospital of Tianjin university of Traditional Chinese Medicine.160 participants are randomized to treatment group(Liu Jun Zi granules) and control group(Liu Jun Zi granules emulsifier):80 participants each.Participants being included in this study must have been diagnosed as prediabetes via western medicine criteria and traditional Chinese Medicine criteria.The primary outcomes is the score of fatigue-scale 14 and the rate of blood glucose return to the normal.The secondary outcomes inludes fasting plasma glucose,2-hour post-meal blood glucose and blood lipid test.The indexes of safety include general medical examination;electrocardiogram(ECG),liver function(ALT) and renel function(BUN,Creatinine) test and record of adverse event. Discussion:The aim of this study is to evaluate the effectiveness and safety of Liu Jun Zi granules for the treatment of patients with prediabetes. Trial registration:Chinese clinical trials register ChiCTR1900022736.