In the research, we report the results on the damp heat stability test for the annealing effect of aluminum and gallium co-doped ZnO (AGZO) thin films. The prepared AGZO thin films (AGZO-RT) by DC moving magnetron sputtering at room temperature were exhibited thicknesses of 150 nm and the sheet resistances of 60-70 Omega/sq. And the part of the deposition, it was annealed in vacuum at 300 degrees C for 18 min. The damp heat tests of the two samples (AGZO-RT, AGZO-AN) were carried out in a chamber with 90% of relative humidity and 60 degrees C of temperature. As the time of the damp heat test increased, the electrical properties of AGZO-RT were more deteriorated than AGZO-AN. The sheet resistance by damp heat to the two samples increased more than three times after 1000 h. The various analytical methods were measured to the electrical, optical and structural properties in the damp heat condition tested about the two thin films, and the results will be discussed. (C) 2011 Elsevier B.V. All rights reserved.