Abstract: At present, the global manufacturing competition pattern is facing restructuring. In order to enhance international competitiveness in China's manufacturing industry, further improving energy eco-efficiency in manufacturing industry is needed. Considering undesirable outputs in the production process, the emissions of waste gas, waste water and solid waste from manufacturing industry are included in the output variables. SBM model is used to calculate energy eco-efficiency in manufacturing industry of 30 provinces from 2000 to 2016 in the paper. Then the regional differences of energy eco-efficiency in manufacturing industry are analyzed. Finally Tobit model is applied to analyze the influencing factors of energy eco-efficiency in manufacturing industry. The results show that the average annual efficiency is 0.44, which is in the middle and low level of development. The differences between provinces are remarkable. On the whole, energy eco-efficiency in manufacturing industry is on the rise. The low pure technical efficiency is the main reason that restricts energy eco-efficiency in manufacturing industry. In the statistical period, the comprehensive efficiency value of the eastern region is obviously higher than that of the central and western regions. The main reason is that the pure technical efficiency of the eastern region is obviously higher than that of the central and western regions. Management and technology level of manufacturing industry in the eastern region is significantly superior to the midwest of China. But the scale efficiency of the eastern region is significantly lower than the midwest. According to Wuli-Shili-Renli system methodology, seven influencing factors, such as economic development level, R&D investment, energy consumption structure and so on are selected, and the model of influencing factors of energy eco-efficiency in manufacturing industry is constructed. The results show that economic development level has the most significant effects on manufacturing energy eco-efficiency in the whole country and the regions. The regression coefficients are 0.079,0.123,0.172 and 0.104 respectively. Apart from economic development level, other influencing factors have different effects on manufacturing energy eco-efficiency in the whole country and the regions. The effect of R&D investment on manufacturing energy eco-efficiency in the whole country and the eastern region is positive,but it is negative to the midwest. The effect of energy consumption structure on manufacturing energy eco-efficiency in the whole country and the eastern region is negative but positive to the central region. The effect of property right structure on manufacturing energy eco-efficiency in the whole country, the eastern and central regions is positive. The effect of openness to the outside world on manufacturing energy eco-efficiency in the whole country is negative but positive to the eastern region. The effect of labor quality on manufacturing energy eco-efficiency in the whole country is positive. The effect of environmental regulation on manufacturing energy eco-efficiency in the whole country and the midwest is negative. In order to improve the overall energy eco-efficiency in China's manufacturing industry and reduce regional differences, in general, the paper puts forward some suggestions such as optimizing industrial structure in manufacturing industry, implementing innovation-driven strategies, increasing the proportion of clean energy consumption, improving corporate governance of state-owned enterprises, reducing the proportion of exports of energy-intensive products, training high-quality manufacturing personnel and improving environmental governance mechanisms. Each region should adopt the applicable countermeasures according to the results of comprehensive efficiency decomposition and the actual regression results of the influencing factors on energy eco-efficiency.

Key words: manufacturing industry, energy eco-efficiency, regional difference, SBM model, Tobit model