Abstract：Objective：According to the theory of “children constitution in lesser yang”，viscera and bowels of children are not well- developed yet， and the defense against pathogen is not strong enough. Thus， children are susceptible to diseases；the diseases are likely to develop and heat can be easily generated from yang. Therefore，the cause of external contraction and fever in children is usually the combination of grater yang，lesser yang and yang brightness. The treatment should focus on lesser yang，which is the center of three yang. Hence the major treatment is harmonizing and releasing the lesser yang， assisted by clearing and purging yang brightness， and dispersing greater yang. The authors named this treatment Sanyang Qingjie method. In clinical treatment of external contraction and fever in children，this method will have good curative effect.