Objective To probe into Electrophysiological characteristics oftelencephalon of the Salamander Hynobiusleechii in process of occurrence and development.Methods Microelectrode technique was used to record extracellularly spontaneous electrical activities of neurons in telencephalon of Hynobiusleechii different periods in occurrence and development.Results The occurrence oftelencephalonrefers to the period when the nervous system from the initial neural tube formation to the emergence of telencephalon tissue morphological characteristics,containing with the early phase of tail bud, the phase of outside-gill and the heart palpitates phase.And, were recorded to the 22, 15 and 11 discharge units.the early phase of tail bud has two kinds of discharge types--single spontaneous firing and consecutive single spontaneous firing, single spontaneous firing is main and accounting for 73%, the discharge amplitude is (0.013±0.005) mV;The phase of outside-gill and the heart palpitates phase both have three kinds of discharge types--single spontaneous firing, consecutive single spontaneous firing and burst spontaneous firing.Consecutive single spontaneous firing is main for the phase of outside-gill, and accounting for 73%,the discharge amplitude is (0.139±0.018) mV.The single spontaneous firing and consecutive single spontaneous firing are main for the heart palpitates phase, and accounting for 73%, the discharge amplitude is (0.112±0.033) mV, (0.029±0.010) mV.The development of telencephalon is the emergence of telencephalon tissue morphological characteristics to mature stage, containing with the incubate phase, forelimbs bud phase,hind limb bud phase, metamorphosis phase and adult phase.Andrespectively,were recorded to the 24, 41, 15,55 and 70 discharge units.The incubate phase and the forelimbs bud phase both have three kinds of discharge types, single spontaneous firing is main and accounting for 48% and 66% respectively, the discharge amplitude is (0.362±0.065) mV and (0.173±0.046) mV respectively;The hind limb bud phase has four kinds of discharge types, single spontaneous firing is main and accounting for 53%, the discharge amplitude is (0.542±0.236) mV;The metamorphosis phase and the adult phase both have five kinds of discharge types, single spontaneous firing is main and accounting for 36% and 31%, the discharge amplitude is (1.384±0.815) mV and (2.585±0.982) mV.Conclusions Following with the occurrence and development of telencephalon, the neuronal excitability increased gradually, the neuronal electrical activities showed diversification.