Objective To provide normal range and mean value of blood biochemical parameters in SPF Wistar rats to serve long-term toxicity test as reference baselines. Methods Blood samples were taken from SPF Wistar rats in different age and sex. By using an automatic chemistry analyzer, a variety of blood biochemical parameters were measured. Results Normal range and mean values of all parameters were obtained. Most biochemical measurements were influenced by age and sex of the rats. The variations of TBil, ALP, TG in rats of different sex and ALP, CK, TG, CHO in rats in different age showed an apparent regularity. Conclusion It is not proper to combine the biochemical data obtained from female and male rats together for statistical analysis in long-term toxicity test. When data are compared with normal values and ranges, attention should be paid to the influence of are and sex of Wistar rats on variation of blood biochemical values.