This paper introduces Professor Cheng Jiazheng’s clinical experience in treating pediatric chronic diarrhea by therapy of invigorating spleen for eliminating dampness. He considers that the spleen deficiency and intense dampness are the key factors of onset and repeated attacking in pediatric chronic diarrhea. He emphasizes the therapy of invigorating spleen for eliminating dampness as the principle for treating root causes,and puts forward the therapy of invigorating spleen and nourishing stomach as the basic treatment for pediatric chronic diarrhea. Meanwhile the treatment should pay attention to the therapy of benefiting qi and nourishing yin,reinforcing kidney yang,warmly invigorating spleen and kidney, which strengthen vital qi and enhance resistance. The treatment could be combined with external application of Chinese medicine. One proven case is presented.