The invention relates to a multi-target detection method for a blood sample, which comprises the following steps: 1) preparing a reagent for reaction, wherein the reagent comprises a coding magnetic microsphere series, and the surface of the coding magnetic microsphere is connected with a specific capture antibody; wherein the encoding magnetic microsphere series comprises magnetic microspheres with different particle sizes, the particle sizes of the magnetic microspheres can be distinguished by a signal of a flow analyzer, and the encoding magnetic microsphere series is used for identifying the types of the microspheres; 2) carrying out reaction and treatment on a blood sample to be detected and a reagent, and removing interference components to form a fluorescent labeled reaction compound based on microspheres; and 3) sending the reaction compound into a flow optical detection system for analysis, obtaining a characteristic signal, identifying the type of the microspheres, and simultaneously detecting multiple targets in the blood sample. Compared with the prior art, the method has the advantages that the coding microspheres have stable characteristics, a whole blood sample is used, multiple detection is realized, and the like.