The invention discloses an electrochemical preparation method of propane, which comprises the following steps: conducting electrolyzing by taking an inert electrode as a working electrode and a counter electrode and taking a solution of glutaric acid in a proton or aprotic solvent as an electrolyte, so as to obtain propane. Propane is prepared by adopting an electrochemical method for the first time, glutaric acid is a renewable green raw material, an aqueous solution system can be completely adopted, and the obtained propane is naturally separated and has a high product purity.