Abstract: OBJECTIVE To study the inflammation hypothesis of polycystic ovary syndrome (PCOS). PCOS is a common clinical endocrine disorder syndrome associated with reproductive dysfunction and abnormal glucose metabolism whose inflammation hypothesis is becoming the focus recently.METHODS This paper studied the function of IL-18 in the process of PCOS through the effect of IL-18 on the key enzyme and androgen activity associated with secretion and synthesis of theca cell androstenedione and 17-hydroxy progesterone. Moreover， it investigated the interference of Qinghua Yure Fang containing serum on PCOS.RESULTS IL-18 promoted the proliferation of theca cells and the secretion of androstenedione and 17-hydroxy progesterone by comparing with the control group (0 pg/mL).The Westernblot and PCR showed IL-18 increased the expression of CYP11A1 and CYP17A1 which were the key enzyme associated with synthesis of theca cell androstenedione and 17-hydroxy progesterone. And IL-18 improved the expression of androgen receptor protein. Qinghua Yure Fang containing serum decreased the secretion of ovarian theca cell androgen and the activity of related synthesis key enzyme and androgen receptor AR.CONCLUSION IL-18 is involved in PCOS caused by chronic inflammation and Qinghua Yure Fang containing serum has certain intervention on PCOS.