Abstract: Objective: To observe the effect of taurine on the excitation of the sciatic nerve trunk in vitro.Methods: The sciatic nerve trunks of toads were isolated and soaked in Ringer's solution containing different concentration of chloride calcium with taurine(40 mmol/L) for 30 minutes.The threshold,refractory period and conduction velocities of action potential were measured by computer.Results: Compared with the normal Ringer's solution group (1.09 mmol/L),the threshold increased and the refractory period shrinked in the Ringer's solution containing higher concentration of chloride calcium(2.18 mmol/L),while the threshold and the conduction velocity of action potential decreased,the refractory period shrinked in the lower concentration(0.27 mmol/L)(P<0.05-P<0.01).Above changes are unobvious in Ringer's solution containing taurine(40 mmol/L) with lower or higher concentration of chloride calcium(P>0.05).Conclusions: The taurine could regulate the excitability of the sciatic nerve trunk in vitro.