The invention belongs to the field of the chemical industry, and in particular relates to a platinum-tantalum bimetallic catalyst for producing n-butanol and a preparation method and application thereof. The catalyst uses platinum-tantalum bimetal as an active component and rare earth metal as an auxiliary agent; a catalyst carrier is silicon dioxide. The catalyst is prepared by loading the activecomponent and auxiliary agent by an impregnation method, and then carrying out roasting. The catalyst is used, ethanol is used as a raw material and nitrogen is used as a carrier and a gas-solid heterogeneous reaction is performed under the reaction pressure of 2-5 MPa and the reaction temperature of 260-350 DEG C to obtain n-butanol. By using ethanol as the raw material to produce butanol, the dependence on petroleum is eliminated, and hexanol with higher added value is co-produced, and the economic benefit is good. The by-product of the reaction is water, which is green and environmentallyfriendly. The preparation method of the invention is simple and has strong replicability and popularization. In addition, the catalyst does not need to be reduced before the reaction, thus reducing the reaction steps, facilitating the operation and reducing the energy consumption.