Abstract: Exploring the environmental efficiency of large-scale pig breeding in various regions in China is of great significance to guide the green development of the pig industry. Based on the panel data of 24 major pig-producing provinces in China in 2010—2020, this paper used the SE-SBM model to measure the environmental efficiency of large-scale pig breeding in China.The results showed that’ the environmental efficiency of large-scale pig breeding was directly proportional to the breeding scale. The environmental efficiency of medium-scale and large-scale pig breeding had improved in fluctuations, and small-scale pig farming had continued to stabilize at a low level. The development of large-scale pig breeding in the eastern and central regions was better than that in the western region; Large-scale pig breeding in Shandong Province, Hebei Province and Chongqing City had a certain exemplary role for other provinces and cities; Redundancy of investment in piglets, disease prevention and control, and excessive chemical oxygen demand and total nitrogen emissions were the main reasons for the loss of efficiency in large-scale pig farming. In order to improve the environmental efficiency of pig breeding in China, it was necessary to appropriately guide the moderate scale development of pig breeding and focus on reducing resource consumption and pollution emissions.