This paper introduces Prof. Xu's academic thoughts on differentiation and treatment of lung cancer based on the theory of “treating both exterior and interior to inhibit the cancer”. Herbs with the function of harmonizing spleen and stomach to strengthen healthy qi, with the function of nourishing kidney essence to consolidate the root and cultivate origin. Medication should be based on disease differentiation, and mechanism of the disease should be considered to during the treatment. One proven case is presented.