Zn1-xCoxO magnetic microspheres have been synthesized by a simple solvothermal process. Different Co2+ dopant concentrations have been used as modifier and proved to be efficient at controlling the morphology and magnetic property of Zn1-xCoxO microspheres. The as-synthesized samples are characterized by X-ray powder diffraction, field-emission scanning electron microscopy, transmission electron microscopy, photoluminescence spectrophotometer and vibrating sample magnetometry. Magnetic hysteresis loops reveal the samples exhibit ferromagnetic loops at room temperature. The meta-saturation magnetization value and coercivity of Zn0.8Co0.2O reach 0.09 emu·g-1 and 15.0 Oe.