The present invention provides a micro-nano structure copper-based catalyst and a preparation method and application thereof, and the micro-nano structure copper-based catalyst comprises the following components by weight: 5%-40% of CuO, 2.5%-20 % of ZnO and 40%-92.5% of Al2O3. The micro-nano structure copper-based catalyst has the advantages of uniform particle size distribution, large specific surface area, strong mechanical properties, smaller copper particle size, high active ingredient copper content and high dispersion, high activity in CO2 hydrogenation operation, good stability, low cost, simple preparation, easy industrial expanding, and the like.