This study aimed to explore the parameters associated with poor ovarian response (POR) to develop an early warning score model (EWSM) for detecting POR in Chinese women undergoing in vitro fertilization, in order to improve the outcomes. Between 2005 and 2011, we recruited 736 patients with POR after IVF and 736 individuals with normal ovarian response after IVF as controls. Clinical parameters were determined to evaluate the ovarian reserve. We then compared the clinical parameters between the POR and control groups, and performed a multivariate analysis to determine the independent factors associated with ovarian response. Receiver-operator characteristic (ROC) was used to analyze the predicted values of individual and combined risk factors. The predicted values were further tested in another cohort of 957 patients. Age, basal follicle-stimulating hormone (bFSH), antral follicle count (AFC), and FSH/luteinizing hormone (LH) ratio were identified as independent factors associated with ovarian response. The EWSM was established using a combination of these parameters. The sensitivity and specificity of the EWSM were 74.6% and 93.6%, respectively. In conclusion, combination of individual risk factors could predict POR with high specificity. The EWSM may help in the evaluation of IVF treatment at an early stage.