The effects of magnetization on the phase composition, microstructure and thermoelectric transport properties of CoSb3 were studied systematically. The magnetic properties of CoSb3 material were also measured at room temperature in order to confirm its magnetic category. The results of XRD and FESEM analysis indicated that the phase composition and microstructure of the CoSb3 were not affected by magnetization. The results of thermoelectric transport measurement showed that the electrical and thermal transport properties of materials were also not affected by magnetization. These results were mainly attributed to the diamagnetism of the CoSb3 material, which were consistent with the results of the magnetic properties measurement. This study is expected to provide a special research perspective for studying the effects of the external conditions on the structure and properties of thermoelectric materials.