Abstract: To improve the environmental efficiency of pig production for pig farmers in Yunnan Province, this study analyzed the pig production input-output of different scales in each monitoring county（cities, districts） of Yunnan Province in 2018 based on the monitoring data of 211 pig farmers in 32 counties（cities, district） in Yunnan Province. In addition, the Super-SBM model with and without expected output was used to calculate the technical efficiency and environmental efficiency of pig production in pig farms of different sizes in each monitored county（cities, district） in Yunnan Province in 2018. The results showed that in 2018, the emissions of pig culture pollutants from range pigs in each monitored county（cities, districts） were higher compared to the scale farms. The number of pig production and other material costs decreased with the increase of scale, while the weight of piglets, the amount of refined feed and the output of main products increased first and then decreased with the increase of scale. In 2018, the production efficiency of pig farmers in monitored counties（cities, districts） in Yunnan Province was high, with an average value of 0.729 8. With the expansion of scale, the average efficiency of pig production technology showed a clear increasing trend. The pig production technical efficiency level of medium-scale pig farms in Yiliang County, Kunming City, Yunnan Province was the highest, reaching 1.096 8. The production technical efficiency level of free-range households in Zhaoyang District, Zhaotong City, Yunnan Province was the lowest among all monitored households（0.514 5）. In 2018, the average production environment efficiency of pigs of in pig farms of different sizes in monitored counties（cities, districts） in Yunnan Province was 0.763 1, and the average production environment efficiency of pig farms of all sizes was higher than that of pig production technology without considering the unexpected output. Among them, the average efficiency of large-scale households increased by 0.094 4, showing the most obvious performance. After considering the undesired output, Longyang District of Baoshan City, Yunnan Province had the highest production environmental efficiency of medium-scale household pigs（1.280 7）, which was higher than 1.035 2 when the undesired output was not considered.In view of this, the countermeasures and suggestions were put forward to actively promote green standardized scale pig production and advocate the combination of breeding and raising and moderate scale mountain pig breeding mode.