In this study, a thermal-gradient chemical vapor infiltration (TG-CVI) process was numeri-cally studied in order to enhance the deposition uniformity within the preform. The compu-tational fluid dynamics technique was used to solve the governing equations for heat transfer and gas flow during the TG-CVI process for two- and three-dimensional (2-D and 3-D) models. The temperature profiles in the 2-D and 3-D models showed good agreement with each other and with the experimental results. The densification process was investigated in a 2-D axisymmetric model. Computation results showed the distribution of the SiC deposi-tion rate within the preform. The results also showed that using two-zone heater gave better deposition uniformity.