以187家中国新能源汽车上市企业为研究对象，在剔除环境因素对企业创新效率影响的基础上，采用三阶段DEA模型分析新能源汽车上市企业创新效率，并从企业自身特征角度，采用Tobit模型对企业创新效率的影响因素进行分析。研究表明，在考虑环境因素的情况下，新能源汽车企业整体创新效率呈现“N”型发展趋势，规模效率是制约新能源汽车企业创新效率提升的关键因素；企业规模、专利存量与企业创新效率正相关，与研发活动密切相关的研发人员和研发支出均对企业创新效率存在积极作用，但研发支出对企业创新效率的正向作用不显著，政府补助强度与企业创新效率负相关。鼓励新能源汽车企业兼并重组、完善政府补助评价机制以及建立新能源汽车企业协同创新平台是提高新能源汽车企业创新效率的关键措施。

Nowadays, the government and new energy vehicle companies have gradually increased their investment in innovative resources for new energy vehicles to increase the innovation output of new energy vehicles. But what follows is the problem of diminishing marginal output of new energy vehicle innovation, and the traditional model of "high input and high output" may no longer be applicable. Correspondingly, the inherent law of diminishing marginal output of corporate innovation and increasing marginal cost of corporate innovation input may inhibit the innovation efficiency of new energy vehicle companies. Most of the present studies carry out in-depth and detailed research from the aspects of innovation stage division and DEA model improvement, ignoring the actual impact of environmental factors on the innovation efficiency of new energy enterprises.#br#This paper selects 187 new energy vehicle listed companies as research samples to make an empirical analysis. First, regional openness, labor quality, technical market environment, technical foundation, and environmental regulation are selected as environmental factors, and the three-stage DEA method is used to measure the influence of environmental factors and the innovation efficiency of new energy vehicle enterprises; second, equity concentration, enterprise patent stock, employee quality, government subsidy intensity, enterprise-scale, financing structure, number of R&D personnel, and R&D personnel are selected based on the measured innovation efficiency value of new energy vehicle enterprises. By taking the expenditure as an explanatory variable, the Tobit model is used to study the influencing factors of the selected variables on the innovation efficiency of new energy vehicle enterprises.#br#The results show that the innovation efficiency, pure technical efficiency and scale efficiency of 187 new energy companies are 0.14, 0.26, and 0.59 respectively, indicating that the overall innovation efficiency of new energy vehicle companies is not high. Pure technical efficiency may be the main factor responsible for this phenomenon. Without removing environmental factors and random errors, the innovation efficiency of listed new energy vehicle companies presents an inverted N shape, with the average value fluctuating around 0.15, the average pure technical efficiency fluctuating around 0.25, and the average scale efficiency fluctuates about 0.6, and the low pure technical efficiency of new energy vehicle enterprises is the main reason for the low innovation efficiency, indicating that new energy vehicle enterprises have much room for improvement in internal management. After excluding the impact of environmental factors on innovation efficiency, the innovation efficiency of listed new energy vehicle companies is generally stable, and the development trend has changed, showing an N-shaped development, indicating that environmental factors have had a substantial impact on measuring the innovation efficiency of new energy vehicle companies. It is necessary to use the three-stage DEA model to measure innovation efficiency after eliminating the influence of environmental factors. From a specific analysis, the innovation efficiency and scale efficiency of new energy vehicle enterprises are at a low level, and the pure technical efficiency is at a high level of 0.9. Therefore, it is analyzed that the reason for the low innovation efficiency of new energy vehicle enterprises is no longer pure technical efficiency, and the low scale efficiency has become the key factor restricting the low innovation efficiency of new energy vehicle enterprises.#br#The Tobit model is used to study the influencing factors of the selected variables on the innovation efficiency of new energy vehicle enterprises. The results show that the characteristics of enterprises themselves have different degrees of influence on innovation efficiency. R&D expenditures promote innovation efficiency but are not statistically significant, and R&D personnel is positively correlated with innovation efficiency at the 1% level. At the level of 1%, ownership concentration has a significant role in promoting the innovation efficiency of enterprises. Enterprise patent stock at the level of 1% promotes the improvement of enterprise innovation efficiency. At the 1% level, there is a positive relationship between enterprise-scale and enterprise innovation efficiency. Both the government subsidy intensity and the financing structure have a negative impact on the innovation efficiency of enterprises at the level of 10%.#br#Compared with previous studies,this study considers the impact of environmental factors of new energy vehicle companies on innovation efficiency, instead of using traditional DEA methods and stochastic frontier analysis methods to calculate innovation of new energy vehicle companies. Second, based on the existing research foundation of new energy vehicle enterprises, the study selects the commonly used factors affecting enterprise innovation efficiencies, such as ownership structure, government subsidies and employee quality, and further explore the influencing factors of enterprise innovation efficiency excluding environmental factors.#br#