Abstract: The moisture-resistance properties of PECVD SiC_x thin films were studied by using orthogonal experimental design. By evaluating the moisture permeation rate in SiC_x films, the effects of the deposition parameters on the moisture-resistance capability of SiC_x film were revealed. The experiment results indicate that the moisture-resistance capability of SiC_x film was mostly influenced by RF frequency and precursor gas flow ratio. It was also found that the optimum deposition conditions of PECVD SiC_x films with respect to the moisture-resistance capability was under high frequency (13.56 MHz), low methane flow ratio, and relatively high RF power (120W). The effect of reactive gas pressure needs further investigation.