Objective To study the relationship between Lidocaine blood drug level and the cause of death from Lidocaine anaphylactic shock. Method Comparing and analyzing the blood drug levels by HPLC between two groups of people whose various indexes are normal before the surgery. Group 1 included 8 cases who accepted Lidocaine as anesthetic and died from Lidocaine anaphylactic shock. Group 2 included 11 cases who also took Lidocaine as anesthetic and passed the surgery smoothly. Results Lidocaine blood level of Group 1 (1.61?0. 45mg/L) is lower than that of Group 2 (2. 44 ?0. 47mg/L). Conclusion Lidocaine blood drug level has nothing to do with the cause of Lidocaine anaphylactic shock.