The scale expansion of low-carbon industries and the green transformation of carbon-intensive industries are two sides of the same coin in achieving the “dual carbon” goals. However, research on transition finance supporting the upgrading of traditional existing carbon-intensive industries remains insufficient. The key to examining the effectiveness of transition finance lies in distinguishing whether the supported enterprises are engaging in greenwashing or green evolution. Based on data of Chinese A-share listed companies in the carbon-intensive industries, an empirical study is conducted and offers the following findings: (1) Transition finance not only does not increase greenwashing but also promotes comprehensive green innovation in carbon-intensive enterprises. (2) In terms of the influencing mechanism, transition finance exerts “resource effects” and “signaling effects,” promoting green innovation by improving debt maturity mismatch and attracting green institutional investors. (3) Heterogeneity analysis shows that the positive impact of transition finance on green innovation is particularly pronounced among enterprises in the eastern region, state-owned enterprises, and those with lower levels of managerial myopia. (4) Further industry spillover effects analysis reveals that transition finance empowers green innovation within industries though peer effects and competitive effects. The findings are essential for understanding the effectiveness of transition finance and offer valuable insights for policymakers.