The invention relates to a piperidine compound and a preparation method thereof. The compound is 2-methyl-4-N-tert-butyloxycarboryl piperidine. The preparation method comprises the following steps of (1) adding a compound (1) ethyl crotonate and benzylamine to obtain an intermediate (2); (2) adding the intermediate (2) and methyl acrylate to obtain an intermediate (3); (3) cyclizing the intermediate (3) with sodium hydride as an alkali to obtain an intermediate (4); (4) subjecting the intermediate (4) to high temperature decarboxylation under an acid condition to obtain an intermediate (5); (5) subjecting the intermediate (5) to aminating reduction to obtain the intermediate (6); (6) loading tert-butyloxycarboryl on the intermediate (6) with triethylamine as an alkali to obtain an intermediate (7); and (7) subjecting the intermediate (7) to debenzylation through reduction with palladium carbon to obtain an end product. According to the preparation method, the reaction is carried out by using a closed tank; a reaction time is shortened; and the reaction is thorough.