This article tries to adopt data envelopment analysis window analysis to evaluate the technological innovation efficiencies of seven types of China's industrial enterprises during 2006–15. However, different window widths will lead to very different results. We designate the ideal window width through the scientific method rather than subjective judgments and obtain the efficiencies closer to reality. We also measure the efficiencies under the worst width opposite to the ideal window width to highlight differences. The results indicate that the efficiencies under the ideal width are more reasonable. During 2006–15, the efficiency of medium-sized enterprises was higher than that of large enterprises, that of private enterprises was higher than that of state-owned and state-holding enterprises, and that of foreign-funded enterprises was higher than that of enterprises with funds from Hong Kong, Macao, and Taiwan and that of domestic-funded enterprises. Moreover, the efficiencies of various types of enterprises all maintained upward trends. [ABSTRACT FROM AUTHOR]