Objective: To investigate prevalence and risk factors of pelvic organ prolapse in women underwent routine gynecologic health care in Peking Union Medical College Hospital (PUMCH)., Methods: From Jan. 2008 to Aug. 2009, 972 women underwent gynecological health care in PUMCH were enrolled in this study. Questionnaires and pelvic examinations were given. The pelvic organ prolapse quantitive examination (POP-Q) system was used as the assessment tool., Results: (1) Among all participants, the mean ages were (42 ± 10) years (range 22 to 78 years), the mean height were (162 ± 5) cm (range 142 to 180 cm), and the mean weight were (59 ± 8) kg (range 42 to 91 kg). 83.8% (815/972) of women were multipara. The mean total vaginal length (TVL) of 972 women was 8.20 cm. No women met the standard of pelvic organ prolapse, while 35.5% (345/972) of women presented mild posterior vaginal descent and 96.7% (940/972) presented mild anterior vaginal descent, all of them were asymptomatic. (2) The length of genital hiatus (gh), TVL and C, D proximal to the hymen in nullipara were (2.26 ± 0.32), (8.08 ± 0.30), (-7.08 ± 0.24) and (-8.08 ± 0.30) cm, which were significantly less than (2.33 ± 0.39), (8.22 ± 0.35), (-7.14 ± 0.28) and (-8.22 ± 0.35) cm in multipara (P < 0.05). Ap and Pb proximal to the hymen of (-2.87 ± 0.22) and (-2.87 ± 0.22) cm in nullipara were significantly larger than (-2.81 ± 0.25) and (-2.81 ± 0.25) cm in multipara (P < 0.05). When compared with nullipara, the incidence of posterior and anterior vaginal wall protrusion were increased (OR = 1.819). (3) The index of POP-P were compared among women at groups of 22 - 34 years, 35 - 49 years and more than 50 years (P < 0.05). Those index did not show statistical difference between women at group of 22 - 34 years and group of 35 - 49 years (P > 0.05). However, those in women at group of 22 - 34 years and 35 - 49 years showed statistical difference when compared with women at group of more than 50 years (P < 0.05). When compared with women at group of 22 - 34 years, the incidence of posterior and anterior vaginal wall protrusion were increased (OR = 1.713, 3.765). (4) Menopause status was associated with severities of all kinds of descent (P < 0.05) and presence of posterior vaginal protrusion (OR = 3.354)., Conclusions: Mild anterior and posterior vaginal descent by POP-Q were common among women in China. The risk of anterior vaginal descent is relatively higher than posterior vaginal descent. However, most of the women with descent are asymptomatic and need no treatment. The most important factors associated with the severity and detectable ratio of descent is parity and age.