To ensure competitiveness in the modem automotive market, process and material planning should be performed concurrently with new car developments. In automotive general assembly shops, thus, new business workflows and supporting environments are inevitable to reduce the manufacturing preparation time in developing a new car in the manner of concurrent and collaborative engineering. Since complete material planning for a whole general assembly system is a huge and complex job, several planners should execute their planning jobs and share information. Therefore, each planner should provide others with his/her results with continuous on-line communication and cooperation. In this research, a web-based system for concurrent and collaborative process and material planning for automotive general assembly via 3D digital mock-up S/W is developed. By using this system, savings in time and cost of process and material planning are possible, and the reliability of the planning result is improved.