This paper develops a duopoly model to investigate a firm’s green technology licensing strategy with corporate social responsibility (CSR). In our model, licensing is conducted by an inside innovator and the patent holder may take CSR activities under a time-consistent emission tax. The result shows that fixed-fee licensing is always the optimal strategy of the patent holder when there is no CSR. In the CSR case, when the reduction degree of abatement cost coefficient is large, the optimal licensing strategy of the patent holder changes from pure royalty licensing to fixed-fee licensing as the degree of CSR decreases. Furthermore, we find that neither conflict nor consistency always exists between social welfare and firm payoff goals. When the degree of CSR is relatively low, fixed-fee licensing is preferred both by the patent holder and the government. Otherwise, when the degree of CSR is relatively high, the government prefers fixed-fee licensing, while the patent holder prefers royalty licensing. Finally, we analyze the effects of CSR behaviors on environment and social welfare. We show that CSR is beneficial for environment, while it is not always beneficial for social welfare.JEL Classifications: D42; M14; I13