Abstract: In practice, carbon tax is an effective supplement to emissions trading system, and is also a key to achieving China's emission reduction targets. Although much research has been done to study the internal mechanism and macro impact of carbon tax, prior literature paid little attention on whether carbon tax affect the strategy and performance of low-carbon technology sharing among enterprise. A differential game model is developed in this paper, which assumed that enterprise low-carbon technology stock is jointly determined by both the efforts of the enterprise low-carbon technology innovation and the external enterprise low-carbon technology sharing. This paper constructs dynamic models under decentralized decision-making with cost-sharing, without cost-sharing, and centralized decision-making respectively, obtain enterprise optimal feedback equilibrium strategies, low-carbon technology stocks and the trajectory of optimal value function of benefits. The results demonstrate that carbon tax can promote enterprise low-carbon technology innovation and sharing to some extent. Meanwhile, this paper found that under the scenario of centralized decision-making, the more the efforts of enterprise low-carbon technology innovation or sharing, the higher the system emission reduction benefits than non-cooperation scenarios. Some factors, such as cost coefficient, cost sharing ratio, etc., will affect the enterprise's decision-making and emission reduction benefits. Finally, the validity of the model is verified through numerical simulation and the sensitivity of the relevant parameters in the scenario of cooperative innovation are analyzed. The results may provide important policy implications for promoting low-carbon technology sharing among enterprises, so as to faciliate the achievement of China's emission reduction targets.