Objective To examine the change of body weight (BW) and blood pressure (BP) in obese rats, clarify relationships between BP and BW and other factors. Methods Male Spraque-Dawley rats were fed either with normal diet (ND) or high calorie diet (HC) for 20 weeks. BW and BP of tail artery were observed biweekly and tetraweekly respectively; serum leptin and fasting insulin (FINS) were detected by enzyme-linked immunoadsordent assay (ELISA) and radioimmunoassay (RIA) respectively. Fasting plasma glucose (FPG) and free fatty acid(FFA) were measured by conventional means. Results BW, abdominal fat weight (AFW), ratio of abdominal fat weight to body weight (R_ F/W), systolic blood pressure (SBP), diastolic blood pressure (DBP), serum levels of leptin and FINS, FPG, FFA increased in the HD group after 20 weeks diet intervention (P<0.05 or P<0.01). SBP was strongly correlated with BW, leptin, FINS and FFA (P<0.05), DBP was correlated with FFA (r=0.47, P<0.05). In addition, leptin was positively correlated with BW, AFW, R_ F/W, FINS and FFA (P<0.05 or P<0.01). Conclusion In this study of high calorie-diet induced rats, the gain of BW is accompanied by increased BP. The obese rats have hyperleptinemia, hyperinsulinemia, hyperglycemia and dyslipidemia which may have important effects on the development of obesity-related hypertension. R_ F/W is the key factor in which affect serum leptin level. Objective To examine the change of body weight (BW) and blood pressure (BP) in obese rats, clarify relationships between BP and BW and other factors. Methods Male Spraque-Dawley rats were fed either with normal diet (ND) or high calorie diet (HC) for 20 weeks. BW and BP of tail artery were observed biweekly and tetraweekly respectively; serum leptin and fasting insulin (FINS) were detected by enzyme- linked immunoadsordent assay (ELISA) and radioimmunoassay (RIA) respectively. Results BW, abdominal fat weight (AFW), ratio of abdominal fat weight to body weight (R_F / W), systolic blood pressure (SBP), diastolic blood pressure (DBP), serum levels of leptin and FINS, FPG, FFA increased in the HD group after 20 weeks diet intervention (P <0.05 or P <0.01). SBP was strongly correlated with BW, leptin, FINS and FFA ), DBP was correlated with FFA (r = 0.47, P <0.05). In addition, leptin was positively correlated with BW, AFW, R_F / W, FINS and FFA (P <0.05 or P <0.01). Conclusion In this study of high calorie-diet induced rats, the gain of BW is accompanied by increased BP. Hyperleptinemia, hyperinsulinemia, hyperglycemia and dyslipidemia which may have important effects on the development of obesity-related hypertension. R_F / W is the key factor in which affect serum leptin level.