<p>Carbon emission trading policy not only reduces carbon emissions but also promotes green technological innovation. This study employs difference-in-difference-in-difference model to assess the impact of China’s carbon emission trading policy on both local and national green technological innovation. Furthermore, the effect of carbon emission trading policy on strategic innovation and substantive innovation is compared. Additionally, a heterogeneity analysis is conducted to examine the green technological innovation behaviours among different types of power enterprises. The results illustrate that after implementing the local pilot policy, green technological innovation patent applications in power enterprises in pilot areas increased by 34.9%. Similarly, following the implementation of the national policy, green technological innovation patent applications in power enterprises increased by 45.2%. Regarding innovation quality, after the implementation of the local pilot policy, power enterprises demonstrated a 25.9% increase in substantive innovation and a 29.9% increase in strategic innovation, respectively. Following the implementation of the national policy, power enterprises exhibited a 21.9% increase in substantive innovation and a 39.2% increase in strategic innovation, respectively. In addition, the carbon emissions trading policy has a positive impact on the green technological innovation of state-owned enterprises and large-scale enterprises. Finally, specific policy implications are proposed to promote green innovation in enterprises.</p>