This paper introduces Professor Li Xiangyun’s experience in the differentiation and treatment of polycystic ovarian syndrome(PCOS)with phlegm-dampness syndrome. He considers that the main pathogenesis are dysfunction of spleen in transportation and abnormal metabolism of body fluid that cause the dampness accumulation and phlegm generation,blockage in Chong and Ren Channels and uterus,which present phlegm-dampness as the manifestations and spleen deficiency as the root cause. Drugs for invigorating spleen and drying dampness can be used and combined with qi regulated medicines to enhance the effects of removing phlegm. Modified Cangfu Daotan Decoction is the recommend prescription. The commonly used couplet medicines for dissipating phlegm and eliminating dampness include Rhizoma Acori Tatarinowii and Lapis Chloriti,Herba Lycopi and Rhizoma Alismatis,Rhizoma Atractylodis Macrocephalae and Rhizoma Atractylodis,Herba Agastaches and Herba Eupatorii,Rhizoma Pinelliae and Caulis Bambusae in Taenia,Radix Aconiti Lateralis Preparata and Ramulus Cinnamomi. According to syndrome differentiation,the couplet medicines are selected or separated and used in combination,and properly regulated combined with menstrual cycle.