The disclosure relates to a current stimulator, which comprises a high voltage output module, a voltage control module and a charge pump module. The high voltage output module includes a plurality of stacked transistors, and receives an input control signal able to turn on/off the current stimulator and a first voltage. A second voltage is generated by adding the voltages output by all the transistors to the first voltage and then output to the voltage control module. The voltage control module outputs a voltage control signal able to stabilize the stimulus current for the load according to the second voltage and the load impedance variation. The charge pump regulates the first voltage according to the voltage control signal, and outputs the regulated first voltage to the high voltage output module. Thereby, the current stimulator can adaptively stabilize the stimulus current, responding to load impedance variation.