Abstract: 2D C/C composites of 24mm thickness were prepared by chemical vapor infiltration (CVI) for 25.5h using liquefied petroleum gas as carbon source in a cold furnace, where 2D preforms were heated by passing electrical current through them. The rapid densification mechanism of the process was investigated, and microstructures of the materials were observed. Results show that CVI can be used to prepare C/C composites with uniform structure and good mechanical properties in a shorter time. The mechanism of rapid densification by CVI includes magnetic attraction of radicals, electric deposition of radicals, and dehydrogenation and aggregation of radicals.