It is reported in the literature that the formation of Al 4C 3 can affect the interface reaction of Gr-Al-Si composites. In this paper, however, the results showed that the presence of a small amount of Al 4C 3 phase in raw materials is beneficial to improve u-niform distribution of graphite without detriment to tensile strength of the materials at high temperature. An alternative available approach was presented for preparing qualified Gr-Al-Si composite in gravity casting. The proper Al 4C 3 phase formation temperature ranged from 550 to 600 ℃. Amount of Al4C3 can be measured by X-ray quantitative analysis.