Objective To study how the chief organs of male Wistar rats were affected after a number of blood collections through their orbital cavity at different intervals. Method The experimental group had blood collection with an interval of 3 days，7 days and 10 days respectively. The blood was collected through orbital venous plexus and with once 1 mL，3 times totally. The control group had once blood collection after the experimental group got it the last time with only 1 mL. Their weights were measured when blood was collected and the Wistar rats were killed after all the collections had been done with their organs ( heart，liver，kidney，spleen，thymus) being weighted the coefficient of the organs. Result The blood collection was done with an interval of 3 days. The significance existed in the rat’s liver and kidneys’coefficient( p< 0. 05) . If the blood was collected with an interval of 7 days and 10 days，there was no any significant difference.Conclusion The blood collection with an interval of 3 days has an influence on the rat’s liver and kidney coefficient and that of 7 days or 10 days has no influence on them.