Optical emission spectroscopy (OES) is an effective method for plasma measuring and diagnosing. OES is used to in-situ measure the hot filament chemical vapor deposition (HFCVD) plasma of acetone/H2/Ar system and methane/H2/Ar, respectively. The type, intensity and the influence of carbon source classes, especially the pressure for acetone/H2/Ar on the spatial distribution in HFCVD plasma are investigated. The results show that main groups are basically the same under different carbon sources, but the differences of spectral distribution are obvious. In acetone system, the intensity of CH is the largest, and there is no H2 spectral lines. Ha line decreases with increasing the pressure, and other groups have a maximum value at nearly of 3.5 kPa. However，in methane system, H2 spectral line is obvious and the intensity of CH is the largest. Ar groups in two systems appear differently in spectral peak corresponding to the wavelength, which is 433.36 nm in acetone system and 794.8 nm in methane system.