Abstract: The glow discharge polymer (GDP) coatings with the thickness from 1 to 2.5 μm were deposited at KBr crystal substrate with different parameters. Infrared characteristic and H/C ratio of GDP coatings were characterized by Fourier transform infrared absorption spectroscopy and element analysis, respectively. The effects of parameters on the ratio of SP³(CH_x) and SP²(CH_x) were investigated. Based on the infared results, the influence of parameters on discharge efficiency of gas was discussed. The interaction between the active segments and the surface was analyzed in the deposition process. With pressure decreasing, the proportion of the SP³(CH₃) and H element will decrease, while the proportion of the SP²(CH₂) and C element will increase. Increasing the radio frequency power or the ratio of T₂B and H₂ can get the same result.