A high-linearity testing stimulus signal generator comprises a signal collection unit receiving an input current signal, a waveform conversion unit connecting with the signal collection unit, a first voltage-to-current conversion unit connecting with the waveform conversion unit, a delay unit connecting with the waveform conversion unit, a second voltage-to-current conversion unit connecting with the delay unit, a current comparison unit connecting respectively with the first voltage-to-current conversion unit and the second voltage-to-current conversion unit, an error calculation unit connecting with the current comparison unit, and a compensation unit connecting with the error calculation unit. The above-mentioned structure forms a feedback mechanism to perform compensation adjustment to promote the linearity of the output signals. Thus, the present invention can generate high-accuracy testing stimulus signals.