Due to the shrinking resources, the traditional linear economy must be replaced by a new economy - circular economy. The concept of circular economy was proposed by the Ellen MacArthur Foundation, with the support from many large multinationals. It is an alternative economic model aiming to keep resources and materials in closed cycling within economic systems, and eventually eliminate the concept of waste. The circular economy model has four components. The first component is resource efficiency, which reduces outputs of harmful substances while minimizing the amount of waste generated. The second component is product design and capital investment, which involves changing product designs, to make them easily disassembled, reused, recycled and upgraded. Thirdly, renewable and cyclic utilization requires further investment on products' materials, components and energy source, as well as forming a renewable utility network with a wide range of resources inputs and outputs. Lastly, integrated economic system involves developing capital and financial mechanisms to promote the transition from linear to circular economy, particularly those related to sustainable production and consumption. It is believed that circular economy is the future of economic development, and it can bring a lot of social and economic benefits. For example, it can help alleviate the resource scarcity problem, encourage innovation, create jobs, reduce waste and preserve the environment. Moving forward with this concept requires tremendous technological and institutional breakthroughs. Therefore, all sectors of our society must come together to support, promote and develop circular economy. We believe that a circular economy system will be fundamental to achieving a sustainable world.