Objective：By tracing the concept of stomach-qi of Chinese medicine，the author explored the connotation of stomach-qi theory in physiopathology， analyzed the relationship among stomach-qi protection theory，the protection of modern gastrointestinal function and enteral nutrition support as well as the guiding role of stomach-qi protection theory in treating critical illness.And the author took some treatment strategies as an example，like warming yang and benefiting qi to nourish earth and protect the presence，acrid opening and bitter descending to regulate the spleen and balance the stomach，and purgation and purging heat and removing blood stasis and strength centralization，thus to elaborate the specific application of the stomach-qi protection theory in the treatment of critical illness.