The present invention belongs to the technical field of nanomedicine, and relates to a method for preparing a therapeutic protein-loaded nanoparticle, as well as a therapeutic protein-loaded nanoparticle, a suspension and a pharmaceutical composition comprising the nanoparticle, and a pharmaceutical preparation comprising the nanoparticle, the suspension or the pharmaceutical composition. The present invention further relates to a use of the nanoparticle in manufacture of a pharmaceutical composition, wherein the pharmaceutical composition is useful in prevention or treatment of a disease that can be prevented or treated by the therapeutic protein comprised in the nanoparticle.