Based on the density functional theory (DFT), studied the bulk properties of the wurtzite ZnO such as lattice parameters, bulk modulus, band structure and the density of state by using a plane-wave ultrasoft pseudopotential technique. The theory predicts that the ZnO is a direct band gap semiconductor material, and the bottommost conduction band and the top of valence band are located in the G point of Brillouin zone. The calculation results agree well with the results in other literatures, and provides theoretical basis for the design and application of optoelectronic materials of ZnO.