The present invention relates to a novel interleukin 2 (IL-2) mutant. The present invention also provides a fusion protein, an immunoconjugate comprising the IL-2 mutant, and a nucleic acid encoding the IL-2 mutant, a vector and a host cell comprising the nucleic acid. The invention further provides a method of making the IL-2 mutant, a pharmaceutical composition comprising the IL-2 mutant, and a therapeutic use of the mutant.本發明涉及新型白介素2(IL-2)突變蛋白。本發明還提供包含該IL-2突變蛋白的融合蛋白、免疫綴合物,以及編碼該IL-2突變蛋白的核酸、包含該核酸的載體和宿主細胞。本發明進一步提供製備該IL-2突變蛋白的方法、包含該IL-2突變蛋白的醫藥組成物和該突變蛋白的治療用途。