The invention discloses a vaccine adjuvant for a swine enzootic pneumonia vaccine, which mainly comprises levamisol, polysaccharide in Chinese herb, chitosan and phosphate buffer solution. Each ml of solution of adjuvant contains 2 to 10mg of levamisol, 20 to 100mg of polysaccharide in Chinese herb, 3 to 15mg of chitosan and the balance of phosphate buffer solution. A preparation method comprisesthe following steps of: preparing high concentration mother solution; and preparing low concentration adjuvant solution. After the adjuvant and the swine enzootic pneumonia vaccine are mixed according to a certain ratio, the swine enzootic pneumonia vaccine containing the adjuvant is prepared, and can obviously improve immune stimulatory capacity of the vaccine and improve the protective effect of the vaccine. The adjuvant also has the advantages of simple and convenient preparation method, stable performance of the adjuvant, contribution to mass production and the like. When the adjuvant is applied, the swine enzootic pneumonia vaccine and the adjuvant are mixed according to the certain ratio, and then intramuscular injection immunity is carried out, so that the intramuscular injection immunity of the swine enzootic pneumonia vaccine is realized, and the defects of the conventional pulmonary injection immunity are overcome.