Abstract: RTM process is considered as an affordable and environmental friendly manufacture technology for the advanced composites. One of the major difficulties of RTM applications is related with complex resin flow behavior during mould filling. A mold filling simulation tool, named BHRTM-2, was developed based on numerical models of RTM process and FEM/CV method. BHRTM-2 was developed in windows environment and a powerful snapping function was also provided, which let an operator easily determine the injection and vent locations. The automatically mashing function for complex plate shape part was also featured. The pressure field, resin flow front, filling time and dry spot of mold filling can be predicted with the simulation tool. The theoretical and experimental verifications of the mold filling simulation were well illustrated and case studies were also given in the research. The research will provide an affordable and user friendly simulation tool for RTM process.