Without exception, all medium-sized and small enterprises survive in a special commercial ecosystem, and they seek for survival and development through energy exchange with the exterior environment. Based on investigation of the ecosystem and market environment, this book analyzes and comments on relevant environmental factors in Jiangsu and Zhejiang Provinces where medium-sized and small enterprises develop relatively faster. It proposes that construction of policy systems from three dimensions (i.e. time, space, and industry) is beneficial to their development and innovation. Based on profound analysis of the environment optimization, service system, financial policy, and innovation policy, the book presents several valuable proposals.