Abstract：Treatment based on syndrome differentiation is the soul of the clinical practice of Chinese medicine. In the face of complex diseases， accurate syndrome differentiation is the fundamental guarantee of the curative effect of Chinese medicine. Thetheory of concurrent qi proposed by LIU Wansu，which uses "wind，heat，dampness，fire，dryness and cold" to summarize the pathogenesis of various internally-contracted and externally-contracted diseases or diseases similar to the transformation of six qi(natural climatic factors)， has important guiding value in analyzing the pathogenesis of complex diseases. Taking the common clinical cases of wasting-thirst complicated with chest impediment as an example，the author tried to discuss the pathogenesis of the disease from the perspective of "concurrent qi"， and concluded that the basic pathogenesis of it was mainly： concurrent dampness and stasis， concurrent dampness and heat， concurrent heat and stasis，concurrent cold，dampness and blood stasis，as well as concurrent wind，heat and stasis. It can provide a way of thinking for the clinical syndrome differentiation of Chinese medicine.