CuIn0.7Ga0.3Se2 (CIGS) thin films were successfully deposited by chemical spray method under air environment and then the as-deposited films were annealed in a furnace. In order to study the influence of annealing temperature and condition on the properties of the CIGS films, annealing temperature was varied from 200 degrees C to 500 degrees C under nitrogen as well as in selenization conditions. The annealing temperatures and conditions exerted an effect on the properties of the prepared thin films. Based on the XRD measurements, the optimum annealing condition to synthesize the CIGS thin films was 500 degrees C under both conditions. The crystalline structure of the film annealed at 500 degrees C was in good agreement with the tetragonal structure in the reference. The surface morphology of the thin film under selenization condition was smooth, dense with lager grain size. XRD, SEM, UV-vis, XPS and ICP-AES were employed to study the influence of annealing temperature on the physical properties of the films.