To investigate the methods of developing type II diabetic rat models, 12 male Wistar rats aged 12 months were adopted in the experiment. Firstly, the rats were naturally fed with high-fat food for four months, then the rats were weighted and their fasting blood glucose (FBG) levels were measured. Then, each rat was injected with a small dose of streptozotocin (STZ) solution (dose: 20 mg/kg, density: 10 mg/mL) for three times and their FBG levels were measured again within one week after each injection. Subsequently, the rats were considered as type II diabetic models when their FBG values were higher than 11.1 mmol/L. The results show that the weights of Wistar rats increase significantly after feeding with high fat diet for four months. Besides, the FBG levels of the rats increase from 5.6±0.7 mmol/L to 22.9±2.7 mmol/L with a significant difference (P＜0.01). Furthermore, the averaged FBG level of the rats is significantly higher than the standard FBG level of 11.1 mmol/L and with a successful rate of 83.3%. In conclusion, the proposed method can develop type II diabetic models with Wistar rats.