Construction and engineering is one of the world largest industry. Yet, it Is one of the most inefficiently operated industry. Since buildings are not constructed by mass production, construction projects usually require intense communication and collaboration between participants, who are usually widely dispersed. That is the main reason for the inefficiency. eWorks21 that we developed in this research, is a project management system that can improve communication and collaboration among project participants using the Internet. eWorks21 can reduce project life-cycle, costs, and increase revenue, resource utilization, controls, transparency, and competitiveness, which will eventually provide infrastructure for knowledge management of construction projects. In this research, we classified currently available project collaboration systems, and analyzed the benefits gained by using project collaboration systems. Then we describe the implementation of eWorks21, and discuss employment and utilization strategies of project collaboration systems.