In this work, the effect of terahertz (THz) radiation on the excitability of hippocampal neurons is studied by changing the neuronal membrane potential and using hippocampal neurons in Sprague Dawley (SD) rats irradiated by a THz source with frequency of 0.1 THz and power density of 2.65 mW/cm 2 for 5, 15, and 25 min, respectively. The results show that THz irradiation for 15 and 25 min causes a significant depolarization of the hippocampal neurons, thereby increasing neuron excitability. To explore the mechanism behind this THz radiation-induced excitability of neurons, the intracellular concentrations of Ca 2+, Na +, and K + are determined. The results show that Ca 2+ and Na + concentrations in the hippocampal neurons increase and K + concentration decreases after irradiation by the THz source. Our study shows that the irradiation with frequency of 0.1 THz and power density of 2.65 mW/cm 2 can promote neuronal excitation by regulating the concentration of charged ions in the hippocampal neurons. This finding may provide the preliminary experimental basis for the application of THz radiation technology to the biomedical field.