The invention discloses a preparation method of a sulfuration mode propane dehydrogenation catalyst. The method comprises the following steps: 1, preparing alumina by adopting a sol-gel technology, and introducing La, Sn and alkali metal sulfide in a glue forming process; 2, supporting a dehydrogenation active component to an alumina carrier prepared in step 1 through adopting an immersion technology; 3, introducing an alkali metal assistant or to a catalyst precursor obtained in step 2, or co-immersing the alkali metal assistant component and the dehydrogenation active component in the carrier; and 4, introducing a hydrogen and water vapor mixed gas into the catalyst precursor obtained in step 3, reducing, sulfurating, and dechlorinating to obtain the sulfuration mode propane dehydrogenation catalyst. The catalyst has the advantages of simple preparation process, full sulfuration, effective reduction of the loss of the alkali metal assistant, and improved long-cycle running activity stability.