ABSTRACT: In modern cities, space congestion will significantly increase building energy consumption (for example, insufficient lighting and poor ventilation caused by congestion). Therefore, optimizing space is a prominent  approach to optimizing urban energy management, and the renewal of leftover space is considered with great  potential. This research first focuses on worldwide cases that show the current approaches to reuse these leftover  spaces, and then systematically classifies them according to their energy-saving and planning strategies. Influenced by factors such as its state structure and economic system, China and the West show many differences. This study develops“City 360 platform as an innovative method to tackle the following problems in leftover space renewal process: simplification resulting in social inequality, low penetration of renewable energy, insufficient planning of electric vehicle parking spaces, and inclusive planning.“City 360 turns the process of leftover space renewal from an urban simplification into an urban diversification, and responds to green challenges. By Integrating multiple actors into a participative process, renewal of leftover space can balance the power among state, society and market, and maximize energy-saving efforts. The innovative, inclusive multi-level planning tool helps cut energy consumption and promotes the minimizing of carbon footprint in developing urban communities.