The present invention is related to a method for detecting a protein comprising: (1) providing a fusion protein, wherein the fusion protein comprises the protein which is fused with a secondary antibody detected protein tag, wherein the secondary antibody detected protein tag comprises at least one epitope selected from the Fc region of at least one primary antibody which is capable of being detected by a corresponding secondary antibody; (2) contacting the fusion protein with a secondary antibody which binds to the secondary antibody detected protein tag to form a protein/antibody complex; and (3) detecting the protein/antibody complex.