The purpose of this study was to establish a simple and effective risk score for type 2 diabetes mellitus (T2DM) in middle-aged rural Chinese. Total of 5453 participants aged 30-59 years from the Rural Diabetes, Obesity and Lifestyle (RuralDiab) study were recruited for establishing the RuralDiab risk score by using logistic regression analysis. The RuralDiab risk score was validated in a prospective study from Henan Province of China, and compared with previous risk scores by using the receiver-operating characteristics cure. Ultimately, sex, age, family history of diabetes, physical activity, waist circumference, history of dyslipidemia, diastolic blood pressure, body mass index were included in the RuralDiab risk score (range from 0 to 36), and the optimal cutoff value was 17 with 67.9% sensitivity and 67.8% specificity. The area under the cures (AUC) of the RuralDiab risk score was 0.723(95%CI: 0.710-0.735) for T2DM in validation population, which was significant higher than the American Diabetes Association score (AUC: 0.636), the Inter99 score (AUC: 0.669), the Oman risk score (AUC: 0.675). The RuralDiab risk score was established and demonstrated an appropriate performance for predicting T2DM in middle-aged Chinese rural population. Further studies for validation should be implemented in different populations.