Abstract: Purpose/Significance Considering the spillover effect on low-carbon advertising of retailers, a two-tier supply chain consisting of a manufacturer and two retailers was constructed. It aims to study the supply chain decision-making problem of low carbon emission reduction level and low carbon reputation level of products under the effect of advertising spillover. Design/Methodology The article analyzes and compares the game equilibrium of supply chain members in two different situations where only a single retailer invests in low-carbon advertising and both retailers invest in low-carbon advertising. Findings/Conclusions The study found that the advertising spillover effect is conducive to the accumulation of low-carbon reputation of the product, and the low-carbon reputation value of the product in the case of two-way advertising overflow is higher than the corresponding value in the case of one-way advertising overflow. There is a threshold for the advertising spillover strength, and only when the spillover strength is lower than this threshold, the retailer as an advertising investor can maintain a profit advantage, and the two-way spillover of advertising can achieve a win-win situation in which both advertising investors obtain the same improvement advantages.