The present disclosure provides an immunoconjugate includes an antibody comprising an antigen-binding fragment that specifically binds to an epitope in mesothelin, N-glycan binding domain and an N-glycan; a linker linking to the N-glycan; and a payload A and a payload B conjugated to the linker, respectively; wherein the payload A and the payload B are the same or different. A pharmaceutical composition comprises the immunoconjugate and a method for treating cancer are also provided in the disclosure.