The invention belongs to the technical field of biology and particularly relates to a preparation method for haemophilus parasuis specific serum. The preparation method includes the steps that an imported complete Freund's adjuvant is injected under the feet of rabbits to induce popliteal lymph node enlargement; first immunity immunogen is used for performing popliteal lymph node injection and hypodermic injection on the rabbits; then second immunity immunogen is used for performing hypodermic injection on the rabbits; and finally, super-intensified immunization is performed, rabbit blood is acquired, and the serum is gained. The preparation method changes an immunity path, and by inducing the popliteal lymph node enlargement, peripheral immune organs and a center immune system are better activated. The haemophilus parasuis serum prepared through the preparation method has the beneficial effects of being high in valence (IHA antibody valence can reach 210), high in specificity, low in cost and the like.