An isolated monoclonal antibody or the antigen binding portion thereof that specifically binds human VISTA. A nucleic acid molecule encoding the antibody, an expression vector, a host cell and a method for expressing the antibody or the antigen binding portion thereof are also provided. The present disclosure further provides a bispecific molecule, and a pharmaceutical composition comprising the antibody or the binding moieties thereof, as well as a treatment method using an anti-VISTA antibody or the antigen binding portion thereof of the present disclosure.