Based on the theory of “sinking of Qi of middle-jiao”，the pathogenesis of membranous nephropathy was discussed，and the pathogenesis theory of “wet spleen and kidney cause sinking of Qi of middle-jiao” was proposed，in which the external invasion of wind and evil and the loss of middle earth were the precursors，and the deficiency of Qi of middle-jiao and the deficiency of spleen and kidney were the basis of the pathogenesis.In addition，the coagulation of the Qi mechanism and wet stasis obstructing collaterals were the core of the pathogenesis; the poison damage to the spleen and kidneys and the sinking of Qi of middle-jiao were the progression of the disease.The dispersion of the atmosphere and the failure of the internal organs were the outcome of the disease，and the deficiency of Qi of middle-jiao ran through the incidence of membranous nephropathy.The disease should be treated with the method of lifting Yang and raising sinking，and the early regulation of the spleen and kidneys and the prevention of external wind should be emphasized.The middle stage should focus on removing dampness，stasis，and detoxification，lifting Yang，and dredging collaterals.In the late stage，the method of lifting Yang，benefiting the stomach，and detoxifying should be adopted，and the heart and kidney deficiency should be both considered.