Abstract: Precancerous lesions of gastric cancer are a category of chronic diseases of the stomach with a clear risk of becoming cancerous. Early intervention of precancerous lesions of gastric cancer is an essential way of secondary prevention of gastric cancer. Based on the functional characteristics of the spleen and stomach and the theory of cancer toxin, Professor Wu Mianhua believes that emotional distress is the triggering cause of precancerous lesions of gastric cancer; weakness of the spleen and stomach is the basic pathogenesis; phlegm and stagnation is the key pathogenesis; and accumulation of cancer toxin is the pathological feature. Syndrome differentiation should focus on identifying the location, pathological factors, and the nature of the disease; treatment should prioritize soothing the liver and gallbladder and be based on regulating and harmonizing the spleen and stomach, with resolving phlegm and blood stasis as the core and anti-cancer and detoxification throughout the entire process; attention should be paid to the transformation of the pathogenesis; prescriptions and medications should be based on the main principles of regulating qi without damaging yin, nourishing yin without hindering the spleen, removing blood stasis without damaging the healthy qi, and replenishing without aiding evil, so as to give full play to the advantages and characteristics of traditional Chinese medicine and provide ideas and references for the clinical diagnosis and treatment of gastric precancerous lesions.