Abstract: In vigorous development of modern greenhouse industry, multi-span greenhouses are equipped with a large number of devices and involve multiple systems and various types．However, traditional power supply methods have several drawbacks, including poor power supply stability, low energy utilization efficiency, high operating costs, and environmental pollution, which significantly hinder multi-span greenhouse industry further development．To effectively solve above problems, Beijing Academy of Agriculture and Forestry Sciences' multi-span greenhouse was selected as a typical case．Through in-depth on-site investigations, a smart power supply system based on renewable energy was designed combined with actual power consumption needs of multi-span greenhouses and renewable energy sources characteristics and advantages such as solar energy, wind energy, and others．Research results showed that this system could significantly reduce multi-span greenhouse operating costs, remarkably improve energy utilization efficiency and intelligent management level．It has important theoretical and practical significance for protected agriculture sustainable development and industry green transformation and upgrading promotion．