To analysis the rule of prescription for PCOS treated by TCM periodic therapy, and to provide the basis for the improvement of clinical curative effect by analyzing clinical literature. Methods: The authors searched the clinical literature of PCOS, built up a literature data-base by Excel software, processed by SPSS and ana1yzed by Pajek. Results: (1) 51 articles met the inclusion criteria, among which 41 were divided treatment into 4 periods, and another 10 articles divided treatment into 3 periods. The articles all-together included to 151 Traditional Chinese Medicine herbs, among which Chinese angelica, dodder, prepared rehmannia root, Chinese yam, Rhizoma Cyperi, epimedium, chuanxiong rhizome, dogwood, Salvia miltiorrhiza, wolfberry fruit, Poria and Rhizoma Atractylodis appeared with a greater percentage than or equal to 2%. (2) The following were the combination of herbs that were commonly used for the treatment of PCOS (their association frequency were greater than or equal to 20%). The follicular phase: dodder, prepared rehmannia root, Chinese angelica, Chinese yam, epimedium, glossy privet fruit, wolfberry fruit, dogwood, rhizoma cyperi, radix polygoni multiflori; Ovulation: dodder, prepared rehmannia root, angelica, safflower, danshen, Chinese yam, cornus, peach seed, chuanxiong, radix paeoniae rubra, radix paeoniae alba, poria, rhizoma cyperi, spina gleditsiae, epimedium; Luteal phase: dodder, prepared rehmannia root, Chinese angelica, Chinese yam, wolfberry fruit, epimedium, cistanche, dogwood, himalayan teasel root, eucommia, rhizoma cyperi, radix polygoni multiflori; Menstrual period: angelica, radix paeoniae rubra, radix salviae miltiorrhizae, rhizoma cyperi, motherwort herb, herba lycopi, chuanxiong, safflower, peach seed, radix rehmanniae preparata. Conclusion: Analyzing the prescription rules for PCOS treatment with TCM periodic therapy showed that the pathological factors were (Yang) deficiency, blood stasis and phlegme; the location of disease were kidney, liver, spleen; the main rules of treatment in follicular phase period were reinforcing liver and kidney, nourishing yin and blood, and regulating qi-flowing for strengthening spleen; the mainly rules of treatment in ovulation were reinforcing liver and kidney, nourishing qi and activating blood ; the mainly rules of premenstrual phase were rising the kidney yang, and regulating qi-flowing for strengthening spleen; In menstrual period the rules were mainly activating blood and nourishing Yin. The results can provide some guidance for clinical practice.