The invention discloses a platinum/attapulgite catalyst and a preparation method thereof. The carrier of the catalyst is the attapulgite clay; the active component of the catalyst is platinum nanoparticles of which the average particle size is 3 to 5 nm; the mass fraction of the platinum in the catalyst is 0.5 to 5 percent; and the residual component of the catalyst is the attapulgite clay. The preparation method comprises the following steps of: modifying the surface of the attapulgite clay with acid; adding a certain amount of modified attapulgite clay into aqueous solution of platinum salt; adjusting the pH value of the aqueous solution with sodium hydrate; adding aqueous solution of potassium borohydride or hydrazine hydrate dropwise in the aqueous solution under the action of magnetically stirring; filtering, washing and drying the mixed aqueous solution to obtain the platinum/attapulgite catalyst. The platinum/attapulgite catalyst prepared by the method of the invention is high in catalytic activity and selectivity for hydrogenation preparation of cinnamyl alcohol through cinnamaldehyde.