Objective To observe the effects of preservation temperature of blood samples on biochemical measurement. Methods By using automatic biochemical analyzer, the biochemical values of blood samples preserved at different temperature were measured and analyzed. Results The biochemical values of blood samples preserved at different temperature differed significantly. The values of TP, ALB, ALT, CHO and TBil were more sensitive to preservation temperature. Conclusion It is important to unify the preservation temperature of blood samples during chronic toxicity testing studies.