Objective To observe the changes of biochemistry indexes in SD rats after anesthesia. Methods 50 SPF SD rats aged 2 months, 28 males and 22 females were collected blood in 0,5,10,20min after anesthesia, and serum ALT,AST,GLU, BUN ,TP,ALB ,AKP, CREA, CHOL, TG were detected after fasting of 12 hours. Results The biochemistry indexes in SD rats varied as anaesthetic time increases. Conclusion Standaring the blood collecting operation, and reducing the time to wait for collecting blood in postanesthesia SD rats can decrease the changes of biochemistry indexes.