Abstract：Explores the mechanism and clinical application of the method of draining the south and supplementing the north based on HUANG Yuanyu's theory of qi circulation. By analyzing the dynamic model of the central earth's mediation and the four-dimensional rotation in the theory of qi circulation，as well as the pathogenesis discussion of the four-directional visceral manifestations in the 75 th chapter of the Nan Jing（The Classic of Difficult Issues），the authors propose that the central earth-four directions model is the common theoretical model for both the method of draining the south and supplementing the north and the theory of qi circulation. The authors believe that the essence of the pathogenesis of excess in the east and deficiency in the west lies in the dysfunction of the middle energizer，leading to excessive ascent of wood and fire and insufficient descent of metal and water. This imbalance in the ascending and descending of qi results in the non-interaction between water and fire. Therefore， the treatment method involves draining the heart fire in the south to calm the hyperactive liver wood and supplementing the kidney water in the north to nourish the deficient lung metal. Essentially，this method aims to restore the four-dimensional circulation by regulating the central earth axis. The method of draining the south and supplementing the north harmonizes the ascending and descending qi of the central earth and the four directions，providing a practical pathway for the theory of qi circulation. Both approaches emphasize the central regulation to control the periphery，highlighting the wisdom of dynamic balance and the flexibility of syndrome differentiation and treatment in Chinese medicine.