You Ke Fa Hui was written by WANG Quan， a distinguished pediatrician in the Ming Dynasty. WANG not only had a profound knowledge of medical theory but also promoted ancient medical essentials. He often followed the ancient teachings of the sages and oracles when he practiced. This essay tries to provide insights into Wang’s distinguishing diagnosis and treatment features through interpreting the Lung Theory elaborated in You Ke Fa Hui such as the lung’s primary disease， additional syndromes and etiology. WANG made diagnoses based on a combination of the patient’s observed colors and pulse. He chose less herbs and smaller amount of each herb to form very effective prescriptions without being limited to one particular pattern. The chapter of Lung’s Primary Disease not only describes medical theory， provides herbs prescription but also shows medical ethics. Its abundant contents demonstrate a high degree of professionalism which our young generation should respect and learn from.