<p>In order to study corporate social responsibility (CSR) donation strategies and their impacts on corporate performance and social welfare, three duopoly CSR donation game models are constructed. The influence mechanism of the “warm glow” and the intensity of market competition on the CSR donation strategy of brands was first discussed, and then the threshold conditions of CSR donation to achieve a win–win situation between enterprises and society were studied. Finally, government subsidies were introduced. The results suggest that the effectiveness of CSR donations as a competitive strategy for brands hinges on the interplay between the warm glow effect and market competition. Donation strategy is not always an effective way for brands to assume social responsibility, because when the effect of warm glow and the intensity of competition are lower, donation can harm social welfare. But if the warm glow is high and the market competition is not fierce enough, CSR donation can achieve a win–win situation. Government subsidy can compensate for the lack of warm glow and incentivize brands to donate. Under a certain warm glow, only when the intensity of government subsidy matches the intensity of market competition can donation become a win–win strategy for enterprises and society.</p>