To explore the time-dependent of p harmacodynamics of lidocain alkalified solution. Method: On 8:00 am and 8:00 pm, surface anaesthesia and subarachnoid anaesthesia were con ducted in rabbits and 76 cases of surgical patients receiving epidureal anaesthe sia were observed in therapy effect.Results: The results of animal experimental showed the anaesthesia potency and anaesthesia incubatory period were better on 8:00 am than 8:00 pm; the clinical observation also obtain ed asimilar result. Conclusion: These results showed that lidocain alkalified solution had time-dependent of pharmacodynamics.