ZnO thin films were deposited by DC reactive magnetron sputtering, and the samples were annealed from 100°C to 400°C, respectively. With the help of x-ray diffractmeter (XRD), spectrophotometer, and photoluminescence (PL) spectroscopy system, the microstructure, intrinsic stress, optical properties, and PL properties were investigated, respectively. The XRD results reveal that all the ZnO films are found to have the hexagonal wurtzite structure with prominent (002) peak. With the annealing temperature increasing, the grain size increased accordingly. All the samples exhibit compressive stress, and the stress value decreasing with annealing temperature increasing. Optical transmittance spectra investigated that all the samples have high transmittance in visible range. With annealing temperature increasing, peak transmittance rising of the sample were observed. The fundamental absorption edge, which associated with band gap of materials, shifting to longer wavelength is observed too. PL results shows that the sample annealed with 300°C have higher intensity emission peak.