Hydrogenated silicon film was fabricated by using plasma enhanced chemical vapor deposition method. The influence of crystalline volume fraction variation on the thermal conductivity was investigated. The relation between crystalline volume and film thickness was characterized by using spectroscopic ellipsometry with Bruggeman effective medium (BEMA) model. The thermal conductivity of silicon film was measured based on Fourier thermal transmitting law using sputtering platinum as electrode. The results demonstrate that the thermal conductivity of silicon film is proportional to the volume fraction of crystalline silicon, and there is crystalline and thermal conductive gradient between surface and bottom in the microcrystalline film. (C) 2011 Elsevier B. V. All rights reserved.