Green technological innovations ease environmental pressure while favoring the long-term development of enterprises. Owners of innovative green technologies often face a paradox: Green technology sharing heightens product greenness competition, whereas non-sharing may lead to a loss of commercialization benefits and green reputation. This study develops a Stackelberg game model that involves two differentiated manufacturers selling partiallysubstitutable products following green technological innovation. The leader decides whether to share the green technological innovation with the follower, while the follower determines whether to adopt the innovation. By studying product differences from two perspectives, we propose a new utility function and find that factors related to firms' green reputation and costs affect companies' business decisions, and there is no dominant strategy for the followers who need to balance the relationship between the green technology gap and the cost of adopting new products. For industry leaders, sharing green technological innovations is an optimal choice. Interestingly, we find that green technological innovation does not always result in improved environmental benefits. As green reputation rises, firms attain higher levels of environmental sustainability after the implementation of green technology innovations. Conversely, in instances of low green reputation, the overall industry sustainability resulting from green innovations falls below the baseline scenario. Our study highlights the importance of considering multiple factors when evaluating the environmental impact of such innovations.