To effectively mitigate the free-riding phenomenon prevailing in inter-enterprise collaborative carbon emission reduction behavior, this paper establishes an evolutionary game model for cooperative carbon emission reduction based on the spatial public goods game. By introducing incentive-based environmental regulations, the equilibrium solution of the game model is derived and analyzed. Numerical simulations are conducted to examine the impact of three types of incentive-based environmental regulations on the strategic choices of inter-enterprise cooperative carbon emission reduction in China. The research conclusions are presented as follows: (1) when two enterprises both opt for cooperation in carbon reduction, each party can obtain higher benefits compared with adopting non-cooperative strategies. In addition, when the synergistic benefits of cooperative emission reduction exceed the sum of the benefits from one enterprise cooperating while the other does not, and when this sum surpasses the sum of non-cooperative emission reduction benefits and external effects, the optimal choice for both enterprises is to adopt a cooperative emission reduction pattern; (2) incentive-based environmental regulation acts as an implicit incremental cost. Among these, an increase in carbon tax rates will inhibit enterprises from carrying out collaborative emission reduction activities. On the contrary, an increase in carbon emission trading prices and input subsidy coefficients can effectively incentivize enterprises to implement joint carbon emission reduction. This study reveals the dynamic evolutionary path and degree of influence of enterprises’ cooperative carbon reduction under incentive-based environmental regulation, providing theoretical foundations and practical references for facilitating inter-enterprise collaboration on carbon reduction initiatives.