To reduce energy consumption and pollution caused by construction, it is urgent to renew the building concept. Firstly, the connotation of "green" building concept has been systematically analyzed. Secondly, it is pointed that establishing "green" building concept meets the needs of reducing costs, improving quality and users' satisfaction. Then, further, Lean-Flexible Construction is put forward as a scientific way to establish and carry out "Green" Building Concept. It is considered that Lean-Flexible Construction can promote effectively the application of "Green" building concept from four aspects.