PURPOSE: A preparing method of butene from normal butane is provided to obtain butene with the yield of about 26-35 % by using normal butane as a reactant and to effectively restrain byproduct generated from a cracking and isomerization, carbon deposition, and deactivation of a catalyst. CONSTITUTION: A preparing method of butene from normal butane comprises a step of a direct de-hydrogenation of normal-butane by using a platinum-tin catalyst which is dipped in ceria-alumina, or by using a platinum-tin catalyst which is dipped in ceria-alumina. The ceria-alumina is a carrier with a spinel structure and comprises 0.5 weight% or more of the ceria. The amount ot be supported is 0.1-5.0 weight%. The carrier of the tin is 0.1-5.0 weight%.
