Objective To investigate the possible role of nerve growth factors (NGF) and its receptors in ovarian follicle development,and detect the difference between polycystic ovarian symdrome (PCOS) and normal control.Methods Immunohistochemisty was applied to detect the expression of NGF,p75NTR,TrkA in ovarian follicle granulosa cells.Results In 54 cases (including 9 cases of IVM-PCOS,16 cases of IVF-PCOS and 29 cases of IVF-Normal),49 cases showed NGF protein positive in granulose cells with significance difference between groups (P＜0.05),and especially NGF was the strongest expressed factor in IVF-PCOS group but there was no remarkable difference between the other two groups in the expression of NGF.41 were TrkA protein positive,almost all IVF cases were TrkA protein positive while only 2 in IVM and there was no remarkable difference in expression of TrkA between IVF PCOS and IVF Normal(P＞0.05).The cases with stronger expression of NGF or TrkA had higher estradiol level than that of lower expression group (P＜0.05).51 cases had positive expression of p75 NTR protein but there was no significant difference between groups (P＞0.05).Conclusions TrkA is expressed in mature ovarian follicle,and the interaction of NGF-TrkA may be involved in ovarian follicle development,and overexpression of NGF may be associated with PCOS development.