In this study we investigate the determinants of behavior intention to use green IT device for reducing electronic consumption by focusing on the end user aspects of a pro-environmental behavior. We tried to understand motivation theory in explaining the causal relationship between motivation aspects and perceived usefulness. By using a reference group theory, we emphasized on how the reference group moderates the motivations and perceived usefulness relationship. We used Partial Least Square (PLS) to analyze the data sample of 104 and found that intrinsic motivation (perceived enjoyment) is significantly related to the perceived usefulness as well as extrinsic motivation (saving money, legislative pressure) is strongly related to the perceived usefulness. In sum, the perceived usefulness has a strong impact on sustainable use of green IT device. Also, we found that a reference group moderates partially the independent variables and mediation variable.