The invention provides a photoconductive switch manufacturing method based on a SiC substrate, and relates to the technical field of wide bandgap semiconductor material photoelectronic devices. SiC with the thickness of 400 micrometers after polishing serves as a substrate in the photoconductive switch manufacturing method based on the SiC substrate. The photoconductive switch manufacturing method based on the SiC substrate comprises the steps that the SiC substrate is prepared; a SiO2 insulation protective layer is generated through thermal oxidation, and a window is formed through photoetching; in high vacuum low temperature Ar atmosphere, a Ti electrode is deposited on the carbon surface, and a Ni electrode is deposited on the silicon surface; after high temperature rapid thermal processing in the Ar atmosphere, a Au protective film is deposited through a small-size ion sputtering instrument, and a photoconductive switch of a Au/Ti/SiC/Ni/Au different-surface opposite-electrode structure is formed by being encapsulated through transparent Si3N4 after a copper electrode is bonded. According to the photoconductive switch manufacturing method based on the SiC substrate, due to the fact that epitaxy of an n-type or p-type SiC epitaxial layer with high doping concentration is not carried out through devices such as CVDs, the technological process of semiconductors is reduced, the rate of finished products is improved, and production cost is lowered. Technical assurance is provided for the production of devices having hash requirements for large power, high frequency and high temperature resistance in future.