Objective: To investigate the onset time of a compound lidocaine cream on topical anesthesia in mice. Methods: Five strains of mice commonly used in medical experiments (BALA-C/Nude, BALB/C, NOD/SCID, C57BL/6J, C3H) were selected. Compound lidocaine cream was applied on the back respectively, and the acupuncture operation simulated inoculating PDX tumor under the skin was used, and then the expression change, acupuncture evasion response and needle pain response of mice were evaluated by scoring method, and the smaller the response, the lower the score, indicating that the anesthesia effect was better. The time points were: 0,10, 20, 30, 40, 50, 60 min. Results: The response to local anesthesia was different in mice of different strains, but the general trend was as follows: after 40 minutes, the score was generally reduced, indicating that the efficacy of local anesthetic drugs played a role. Conclusion: In mice undergoing PDX tumor mass implantation, it is recommended to start the operation after 40 min after applying compound lidocaine when simple dermatotomy and suture, which is more in line with animal welfare.