Disclosed are a fully human monoclonal antibody specifically binding to a CD137 or an antigen binding portion thereof. On one hand, provided are a CDR/variable region sequence of the antibody and an encoding nucleic acid sequence thereof; on the other hand, provided is a method for treating diseases using the antibody or the antigen binding portion thereof. a fully human monoclonal antibody specifically binding to a CD137 or an antigen binding portion thereof. On one hand, provided are a CDR/variable region sequence of the antibody and an encoding nucleic acid sequence thereof; on the other hand, provided is a method for treating diseases using the antibody or the antigen binding portion thereof.