Retinol-binding protein 4 (RBP4) has been reported involving in the occurrence and development of hypertension. However, to date, few data are available on the correlation between serum RBP4 level and blood pressure (BP) in prehypertension. Therefore, this association was investigated in prehypertensive Chinese. Overall, 160 subjects with prehypertension (Pre-HT group) and 160 subjects with normal BP (NBP group) were recruited in this study. The subjects were divided into the following four subgroups according to body mass index (BMI): obese Pre-HT subgroup; non-obese Pre-HT subgroup; obese NBP subgroup; and non-obese NBP subgroup (n = 80 in each). Anthropometric parameters, systolic BP (SBP), diastolic BP (DBP) and several biochemical parameters were measured. Fasting insulin was evaluated by radioimmunoassay. Serum RBP4 level was measured by enzyme-linked immunosorbent assay. The Pre-HT group had higher levels of serum RBP4 level than did the NBP group (P < 0.001). Moreover, higher RBP4 levels were identified in the obese Pre-HT subgroup relative to the non-obese Pre-HT subgroup (P = 0.005). However, no difference in RBP4 level was identified between the obese and the non-obese NBP subgroups (P = 0.317). RBP4 level was positively correlated with BMI (r = 0.226, P = 0.001), SBP (r = 0.468, P < 0.001) and DBP (r = 0.358, P < 0.001) after adjustment for age, sex, smoking status and alcohol consumption. The results of the multiple regression analyses demonstrated that RBP4 level was independently associated with SBP (β = 0.427, P < 0.001) and DBP (β = 0.338, P < 0.001). In conclusion, serum RBP4 level was significantly higher and closely associated with BP in prehypertensive Chinese.