Chymopapain, one of the four cysteine proteinases of papaya latex, has milk clotting and proteolytic activity. It is mainly used to treat prolapsed intervertebral discs. This paper introduced the preparation of polyclonal antibody of partially purified chymopapain and the identification of the antibody specificity. The polyclonal antibody provides a basis for the further researches and applications of chymopapain.