Abstract:The modern think tank has already been the fifth power in the international and national good-governing. It works together with the global issue solving, the international structure designing, the geopolitics patterning, the national strategy making, law maker counseling, economic development planning, social security concerning, etc. So called the fifth power is after the legislative, the administration, the judicial authority, and the media. In the network world and the information society, based on the great significance and value of the think tank, the paper redefines the modern think tank that should have three main features. Firstly, the modern think tank should be developed based on the cooperative and multidisciplinary by introducing the natural-human-engineering knowledge and tools. Secondly, the three levels of capacity building in the modern think tank are seeking the natural relations, the logic relations, and the functional relations. Finally, the modern think tank should be able to offer the theoretical, strategical, applicable, and emergent outcomes to fulfill the demand of policy makers, therefore to achieve the final goals of monitoring, forecast, and warning, as the reliable national think tank.