The invention discloses a direct current superposed multi-harmonic high-voltage generator, which comprises a voltage regulator, a boosting transformer, a silicon stack, an adjustable resistor, a protective resistor and a sleeve test product. The direct current superposed multi-harmonic high-voltage generator has the following beneficial effects that the direction of the silicon stack is adjusted,so that the positive and negative polarities of the device output direct-current high voltage are adjusted conveniently, and thus the operation and the use of the experimental personnel can be facilitated; the adjustable resistor is provided with a plurality of resistance adjustable values, so that the multi-harmonic content of the device output direct-current high voltage is adjusted, the devicecan generate direct current superposed multi-harmonic voltage waveforms, and thus relevant research of a converter transformer valve side sleeve can be conveniently carried out in a laboratory; the waveforms borne by the two ends of a test product of the sleeve test product are direct current superposed multi-harmonics, so that the actual voltage waveform of the converter transformer valve side sleeve can be simulated; and the adjustable resistor and the protective resistor are arranged in parallel, so that a short circuit protection effect is achieved on the device, and the safety operation performance of the device is improved.