The invention discloses a preparation method and an application of a wool-supported nano Pd-Co catalyst. The preparation method comprises the following steps: 1) carrying out impurities removal, washing and degreasing treatment on wool; 2) adding mercaptoacetic acid, tetrahydrofuran, the degreased wool and concentrated sulfuric acid, adding a plug, at the temperature of 60 DEG C, refluxing for 4-6 h with stirring, washing with water, carrying out suction filtration until the filtrate is neutral, drying, and thus obtaining mercapto wool; 3) adding the mercapto wool into a mixed solution of palladium ions and cobalt ions, adjusting the pH value of the solution to 6.0-7.5, carrying out stirring reaction for 20-40 min at the room temperature, after filtering separation, putting the obtained solid into a 40% hydrazine hydrate solution with a solid-liquid ratio of 1 g:15-30 mL, carrying out ultrasonic reaction for 35 min, filtering, washing with distilled water, drying at the temperature of 90 DEG C, and thus obtaining the wool-supported nano Pd-Co catalyst. The wool-supported nano Pd-Co catalyst has the characteristics of simple preparation method, good stability, degradability, waste reutilization, mild reaction conditions, high catalytic activity, little using amount and the like.