The invention belongs to the technical field of silicon carbide preparation, and specifically relates to a preparation method of a p/n type silicon carbide ohmic contact. The method comprises the following steps: carrying out precleaning and preprocessing on silicon carbide epitaxial wafers, then using an atomic layer deposition technology to form a 3TiC/SiC layer, a 3TiC/xSiC layer and a TiC layer in sequence on each silicon carbide epitaxial wafer, forming Ti3SiC2 layers, transition layers and TiC layers in sequence after alloying heat treatment, and thus obtaining p/n type silicon carbide with an ohmic contact characteristic. By using ALD, each 3TiC/SiC layer is formed on the corresponding silicon carbide epitaxial wafer by controlling a molar ratio, the Ti3SiC2 layers are formed afteralloying heat treatment, the height of a barrier at the position of an interface can be reduced, the ohmic contact is formed with the silicon carbide epitaxial wafers, the method avoids an alloying reaction from occurring on SiC wafers in the silicon carbide epitaxial wafers in the deposition process, and the problems of carbon enrichment and gaps are solved.