A water vapor containing plasma activated bonding process is developed to optimize the bonding quality of Si/Si and glass/glass bondings in air ambient. Sufficient bonding strength was achieved at room temperature with no heating process. Meanwhile, good bonding efficiency was realized owing to the appropriate water molecules adsorbed on the surfaces. The whole processes are performed in low-vacuum and ambient air environment. The water vapor containing plasma activated bonding is thus low-cost and environmentally friendly process.