A non-template CVD method was used to synthesize well-aligned carbon nanotube (ACNT) arrays. Ferrocene was used as a catalyst, xylene as the carbon source. This process carried out in a single-furnace system. The products were characterized by Scanning Electron Microscopy(SEM), Transmission Electron Microscopy(TEM), Energy Dispersive Spectrometry(EDS) and Raman Spectroscopy. The effects of process parameters on ACNT arrays growth were also investigated. The results show that well-aligned carbon nanotubes can be easily grown on polished silicon substrate at 800℃ with catalyst concentration of 0.02mg/L. Under the above conditions the rate of growth of ACNT arrays can reach 25μm/min.