Abstract: An antibody or an antigen-binding fragment thereof that binds to CD228, and an antibody-drug conjugate containing the antibody or antigen-binding fragment thereof. The antibody or antigen-binding fragment thereof has a high affinity to a CD228 protein and an ability to mediate ADCC. The antibody-drug conjugate exhibits an inhibitory effect on various tumors. A nucleic acid encoding the antibody or antigen-binding fragment thereof; a cell containing the nucleic acid; a pharmaceutical composition containing the antibody or antigen-binding fragment thereof, the nucleic acid, the cell or the antibody-drug conjugate; and a kit. The use of the antibody or antigen-binding fragment thereof, the nucleic acid, the antibody-drug conjugate or the pharmaceutical composition in the prevention, treatment, detection or diagnosis of diseases related to CD228.