Promoting technological innovation is an essential issue for enterprises to maintain sustainable development in a highly competitive environment. Previous studies have focused on exploring the linear relationship between intellectual capital and technological innovation, ignoring the possibility of a non-linear relationship between them. This study draws on a dualistic view of intellectual capital and divides it into two elements: human capital and structural capital. Based on the factor endowment theory, we explored the non-linear relationship between intellectual capital and technological innovation, using the data of Chinese A-share listed companies from 2014 to 2019 as the sample, and then analyzed the moderating effect of corporate social responsibility (CSR) on their relationship. The results of the OLS regressions indicated a significant U-shaped relationship between intellectual capital and its elements on technological innovation. This means a “regressive” effect of low levels of intellectual capital on technological innovation and an “incremental” effect of high levels of intellectual capital on technological innovation. Improving CSR could positively enhance the U-shaped effect of intellectual capital on technological innovation. A further study found that the U-shaped effects of intellectual capital and human capital on technological innovation were still supported in state-owned and private enterprises. The U-shaped effect of structural capital on technological innovation was still supported in private enterprises but not in state-owned enterprises. This study explored the relationship between intellectual capital and technological innovation from a unique perspective. It provides a theoretical basis for enterprises to appropriately fulfill their social responsibility and actively promote technological innovation.