Zn_1-x Co_x O (0≤ x≤ 0.10) nano-particles were fabricated successfully via ball milling procedure. The influence of [Co]/[Zn] on the properties of nano-particles was examined employing X-ray diffraction, the energy dispersion of the X-ray (EDX), Scan Electron Microscope (SEM), these measurements exhibit the growth hexagonal wurtzite crystal phase Zn_1-xCo_xO nano-particles with the successfully incorporation of Co⁺² ions in the ZnO lattice. The optical characterization investigated utilizing Ultraviolet-Visible (UV) absorption spectroscopy for Zn_1-xCo_xO nano-particles refers to a red-shift in the optical bandgap with increasing Co ion inside ZnO matrix, this result confirm the bandgap is considerably narrowed with increasing Co ratio. The measurements of magnetization applying vibrating sample magnetometer illustrated a hysteresis loop in Co-doped ZnO nano-particles. Thanks to the variation values of bandgap E_g^opt and magnetic measurements of ZnO nano-particles doped Co% plays a major role for selective coatings of optoelectronics; use as antireflective coating materials, and fabrication of optoelectronic devices.