Herein, the -Fe2O3@carboxyl-functionalized yeast composite (-F@CFYC) was synthesized by direct oxidation of yeast with K2FeO4 and used as a novel adsorbent/heterogeneous Fenton catalyst for removal of methylene blue (MB). The obtained -F@CFYC was fully characterized by scanning electron microscopy, EDX, X-ray diffraction analysis, Fourier-transform infrared, thermogravimetry, and X-ray photoelectron spectroscopy, respectively, and the corresponding results showed that -Fe2O3 nanoparticles were successfully obtained and deposited on yeast surface, as well as more functional groups were introduced/exposed on yeast surface. Furthermore, various influence parameters (eg, contact time, initial pH, and MB concentration) on the adsorption/catalysis ability of -F@CFYC for MB have been investigated in detail under ambient conditions. As a result, owing to the synergetic effect of the loaded -Fe2O3 and the introduced/exposed functional groups on yeast surface, the as-obtained -F@CFYC exhibited high adsorption capacities and good catalysis degradation properties for MB.