The pivot effect of Tianshu (ST 25) was analyzed, which was explored from 5 aspects, named the ascending and descending of spleen and stomach qi, the smooth flowing of liver and gallbladder, the transmission of intestine, the passage regulation of three jiao (triple energizer) and conducting yang from yin. Tianshu (ST 25) governs qi and is in charge of its ascending, descending, exiting and entering. In order to understand the effect and application of such acupoint, the theoretic source should be interpreted at first. Hence, the exploration on the pivot effect of Tianshu (ST 25) in terms of the ascending, descending, exiting and entering of qi activity may provide the guidance to the clinical treatment.