Abstract: This paper addresses the Resin Transfer Molding (RTM) process. The governing equations of resin flow are presented. The major problems involved in fabricating large, high fiber volume fraction components by RTM, are discussed. A boundary-fitted coordinate system and the finite difference method are employed for simulating the resin flow process in the case of two injection ports. The successive resin flow fronts, and the pressure distribution at the final stage are obtained, which is helpful for locating the air vent. Good agreement is reached between the present results and those of other investigations.