Abstract: In order to decrease the manufacturing time and improve the properties of the C/C brake discs，a new process of rapid densification to manufacture C/C brake discs was developed. This process is a method of the isothermal pressure gradient CVI whose precursors are CH₄ and C₃H₈. The CVI (chemical vapor infiltration) time of the discs manufactured by the new process is a half of the CVI time of the discs manufactured by the conventional process whose precursor is C₃H₆. In addition,  the thermal conductivity of the discs produced by the new process has increased by more than 5%，the mechanical properties including tensile strength，compressing strength，bending strength and shearing strength have increased by more than 10%，and the properties of friction and wear have been raised by more than 20%.