The invention provides a kit for diagnosing mycobacterium tuberculosis infection based on tuberculosis specificity IL-31 detection. The kit comprises an IL-31 capture antibody, an IL-31 detection antibody, tuberculosis specific antigen polypeptide, a diluent, a standard substance, a developing solution, a stop solution, a buffer solution, a solid carrier and a micro-plate sealer. The kit is used for detecting the IL-31 expression quantity in plasma, can be used for tuberculosis diagnosis, and is relatively high in sensitivity and accuracy, and fast to operate, so that the diagnosing efficiency of tuberculosis can be improved.