Abstract： This paper introduces the clinical experience of YAN Xingmao using modified Guizhi and Longgu Muli Decoction in syndrome differentiation and treatment of strange sweating. YAN Xingmao believes that strange sweating is caused by yin-yang disharmony，yang floating outward，and yin leakage to the exterior. Guizhi and Longgu Muli Decoction has the effects of harmonizing yin and yang， and subduing yang and securing yin. According to the correspondence of formula and syndrome， syndrome differentiation and treatment can be carried out with modified Guizhi and Longgu Muli Decoction. For example， the additional use of channel envoy medicinals is usually applied with the consideration of sweating areas；or the combined syndrome is treated by combined formula；or astringent medicinals for arresting sweating can help strengthen the sweat-constraining effect；or medicinals for enriching yin and assisting yang can be added to reinforce healthy qi and consolidate the exterior. In short， the flexible syndrome differentiation and treatment with modified Guizhi and Longgu Muli Decoction can help achieve quick effects.