Taking advantage of the glowing discharge technology and plasma mass spectrometry diagnosis technology, the variation rules of positive ion species and energy with power in H2/C4H8 mixture gas are investigated. The characteristic ions are measured and their forming process is discussed. The results show that the intensity of the C-H segment ions in the H2/C4H8 plasma increases with radio-frequency (RF) power increasing, the intensity reaches a maximum at an RF power of 20 W, and then reduces after the RF power has reached 25 W. The relative concentration of m/e 57 (C4H9+) is highest when the power is less than 10 W, and when the power is more than 10 W, the relative concentration of m/e 39 (C3H3+) reaches a maximum. The energy of the C-H segment ions increases gradually with the increase of RF power. The qualitative analyses of H2/C4H8 plasma composition and energy will be beneficial to improving the fabrication technology of glowing discharge polymer coating.