The invention relates to the technical field of erythropoietin, and discloses an erythropoietin detection method based on a magnetic bead as a carrier, which comprises the following steps of: coupling a capture antibody (anti-EPO antibody) on the magnetic bead, capturing EPO in serum by the capture antibody coupled on the magnetic bead, and then adding a biotinylated detection antibody, a'capture antibody-EPO-detection antibody 'immune complex taking magnetic beads as a carrier is formed, then streptavidin coupled enzyme is added to be combined with biotin labeled on the detection antibody, and the immune complex is labeled. The established immunoassay method has ultrahigh sensitivity (19pg / mL) which is improved by 13 times compared with the traditional immunoassay method, the sample dosage (15mu L) is reduced by 13 times compared with the traditional immunoassay method, the sample detection experiment period is shortened to 34min which is far shorter than the traditional immunoassay method (6-8h), the change rule of endogenous EPO in serum can be detected more timely by using the method, and the method has the advantages of high sensitivity and high sensitivity. And a dynamic change process of absorption, distribution, metabolism, excretion and the like of exogenous EPO in a body is supported.