Abstract: In urban renewal, many old industrial plants have not been fully utilized. Most of them still adopt the method of "demolition and large-scale construction, overturning and restarting". Combining old industrial plants with green ecological transformation technology is a very urgent problem that needs to be solved in the renewal and transformation of old industrial plants in our country. It is also the only way to practice the concept of adhering to the harmonious coexistence of human and nature. It is very important to carry out research on the green transformation of old industrial factories. Taking COOMO Furnishings Ltd. transformation project as an example, the described technical points of the old industrial plant green ecological reconstruction and expansion. The space layout was optimized for the original layout, according to the original layout of the addition of earth-covered buildings and L-shaped buildings to ensure the expansion of the used space, while optimizing the site zoning, traffic layout and green space configuration; in terms of the integration of old and new buildings, the concept of "mountain building" was implemented to create a good working environment, and modern concepts were introduced to update the façade of existing industrial buildings, so that the old and new buildings could be integrated; in the field of green ecological practice, the building would be hidden into green vegetation, the planting roofs or photovoltaic power generation, wind utilization and other measures would be introduced to achieve energy conservation and environmental protection.