In this present work, we report a mild and efficient chemical route in preparing Fe3O4@ZnS bifunctional nanospheres. Scanning electron microscopy (SEM) observation and X-ray diffraction (XRD) indicate core-shell structure of the Fe3O4@ZnS nanospheres with the diameter around 400–700 nm. High-resolution transmission electron microscopy (HRTEM) determination reveals high crystallinity of the nanospheres. Magnetic and photoluminesce properties of the nanospheres show that the nanospheres possessed high magnetization saturation value of 58.8524 ∼61.6569 emu/g with strong blue emission under UV irradiation. The optical intensity can be adjusted in our experiments. These properties suggest that the bifunctional magnetic-optical nanospheres promise great potential in the applications of optical imaging and time-resolved fluorescence imaging.