The new energy vehicle enterprises is a strategic emerging industry in China, so more and more government subsidies to promote innovative development are being accepted by new energy vehicle enterprises. What is the innovation efficiency of new energy vehicle enterprises receiving government subsidies? With the acceleration of the process of global economic financialization, whether financial support can promote the innovation efficiency of government subsidies and how enterprises should allocate financial assets have become issues that need to be deeply considered. Based on the annual report data of China's domestic listed new energy vehicle enterprises from 2015 to 2020, the relationship between government subsidies and enterprise innovation efficiency is empirically tested, and the impact of financial support on enterprise R&D innovation efficiency is investigated. The empirical results show that government subsidies are wasteful and fail to effectively promote R&D innovation, and the innovation efficiency of government subsidies is positively influenced by firm nature and firm age, while the total asset turnover ratio, operating cycle and firm size have a negative impact on innovation efficiency. Further research found that there is an inverted U-shaped relationship between financial support and the innovation efficiency of government subsidies. A certain degree of financial support has a positive impact on the innovation efficiency of government subsidies, but excessive financial support has a negative impact on the innovation efficiency of government subsidies. The conclusion provides empirical evidence for the Chinese government to improve the subsidy policy and standardize the development of new energy vehicle enterprises, and has a certain reference value for guiding new energy vehicle enterprises to reasonably allocate financial support.