In the process of combating desertification in China, enterprises have become the main governance body that cannot be ignored and have made good achievements. Some enterprises have positive externalities when producing and operating in the same space, which has a positive effect on reducing operating costs or increasing revenue. To explore how enterprises with such type of features can collaborate to combat desertification, a differential game model was constructed to analyze the optimal combating input level, desertification combating acreage, and revenues of the two enterprises in the non-cooperation mode, unilateral ecological subsidy mode, and bilateral ecological subsidy mode. The results indicate that the bilateral ecological subsidy mode can achieve the best governance effect, and the governance effect of the unilateral ecological subsidy mode is better than the non-cooperation mode. Total revenue of the two enterprises is highest in the bilateral ecological subsidy mode. Both externalities generated by the two enterprises can promote an increase in desertification by combating acreage, which has the strongest influence in the bilateral ecological subsidy mode. Therefore, the two enterprises can achieve a win-win situation by implementing the aforementioned mode. Given that this mode cannot be implemented automatically, we provide a dynamic revenue distribution scheme. The research can provide some macro guidance and decision-making reference for the government and enterprises participating in combating desertification.