Objective To study the pathological morphologic characteristics of invasive pituitary tumors and the affect of expression of Ki-67 and MMP-9 to the tumor invasion.Methods Analyzing 130 cases of pituitary tumor specimens from January 2003 to december 2011,which divided into two groups according to invasion,observe pathological morphologic characteristics through the light and electron microscope and the expression of Ki-67 and MMP-9 via immunohistochemistry (IHC).Results The difference was statistically significant(P ＜ 0.05) between the invasive group and noninvasive group in the incidence rate of pathological morphologic characteristics,such as high nuclearcytoplasmic ratio,cell pleomorphism,nuclear atypia,and nucleoli appearence; nuclear atypia and nucleolus margination in the invasive group were found through the electron microscopy.therein addition,significant statistical differences in the rate of Ki-67 and MMP-9 expressions were found ; the rate was higher in the invasive group than the noninvasive group(P ＜ 0.01).Conclusions the pathological morphologic characteristics of pituitary tumor and the high expression of Ki-67 and MMP-9 were significantly valuable in the diagnosis of tumor aggressiveness,which provided valuable indicators for early clinical diagnosis of tumor invasion.