Severe acute pancreatitis （SAP） is closely related to dysfunction of the spleen-stomach ascent and descent. Due to the influence of modern lifestyle and dietary factors， Qi deficiency in the spleen and stomach has become the pathological basis of SAP. Its pathogenesis is characterized by dampness， heat， pathogenic factors， stasis， stagnation， obstruction， Fu-organs Qi obstruction， pathogenic excess， and healthy Qi deficiency. At different stages of the disease course of SAP， there is a focus on both pathogenic excess and healthy Qi deficiency. It is specifically manifested as Fu-organs stagnation and heat accumulation， as well as pathogenic excess and healthy Qi deficiency， during the systemic inflammatory response phase， intermingling of blood stasis and pathogenic factors， as well as Qi deficiency and blood stasis， during the infection period， and weakness of the spleen and stomach， as well as healthy Qi deficiency and lingering pathogenic factors， during the residual infection period. Based on the theory that "the spleen and stomach are the acquired foundation"， a staged treatment method centered on the core principle of "strengthening healthy Qi to eliminate pathogenic factors" was developed. The staged treatment method included "clearing the Fu-organs to expel turbidity， replenishing Qi to harmonize the stomach， activating blood circulation to expel pathogenic factors， replenishing Qi to relieve pain， promoting digestion to stimulate appetite， and replenishing Qi to invigorate the spleen". In clinical practice， Hewei Tongxie mixture， Yikang mixture， and Shiwei Jianpi Xiaoshi powder were selected for staged treatment of SAP. This article systematically summarized the theoretical basis of traditional Chinese medicine， Western medicine foundation， modern pharmacological mechanisms， and clinical application experience of the staged treatment of SAP with "strengthening the healthy Qi to eliminate pathogenic factors"， providing new ideas for the treatment of SAP with traditional Chinese medicine.