We systematically investigated the recovery ability of some silylation materials for a plasma-damaged porous silica low-k material. In order to evaluate recovery ability, the permittivity and leakage current were measured. The recovery ability is listed in ascending order as ethoxy group, disilazane group, and dimethylamino group, and materials with SiH–(CH<inf>3</inf>)<inf>2</inf>showed a better recovery ability than those with Si–(CH<inf>3</inf>)<inf>3</inf>. Recovery mechanisms were also analyzed using Fourier transform infrared spectroscopy (FT-IR) and thermal desorption spectrometer (TDS). Clear differences in the silylation abilities were observed in the silylation rate as well as the amount of silylation. We focused on trimethylsilyldimethylamine (TMSDMA) and tetramethyldisilazane (TMDS) as the recovery material of vapor phase and both materials showed good recovery characteristics. TMSDMA showed rapid recovery because of its higher vapor pressure. TMDS effectively reduced the amount of absorbed water.