In order to explore the role of local government subsidy policy in the decision-making of port enterprises’ adoption of green technology, the game model between local government and port enterprises was constructed by using the evolutionary game method. Combined with the idea of prospect theory, it made up for the expected effect of income value in the traditional evolutionary game theory, and adopted more appropriate subjective perceived value to construct the profit and loss matrix of both sides of the game based on carbon quota constraints. The results show that when the sum of the subjective perceived benefits of adopting green technology and the transaction cost of purchasing carbon emissions is higher than the cost of investing in green technology, port enterprises will spontaneously choose to adopt green technology. In order to avoid falling into a state of invalid government subsidies, it is necessary to rely on the dual means of subsidies and carbon quotas to form a winwin situation in which port enterprises spontaneously adopt green technology.