This paper considers one of the hot topics in the current society-food quality and safety problem. We analyze the new features of CSR under supply chain management and then analyze its short, medium and long-term effects on the profits allocation;in supply chain management under the perspective of externality. Based on the analysis, the CSR has different effects on the profits distribution in short, medium and long-term ways. The externalities produced by CSR are not an easy way but a step-by-step process. In the short term, it has no obvious effects on manufacturers, retailers and society, the profits of the short term. can not compensate for costs. In the medium term, there are three situations which depended on the specific circumstances. While in the long term, it will improve the Pareto Optimal of society, bring about positive external effects. We can use the J Curve to manifest the relationship among short, medium and long-term. Finally, we conclude strategic choices for the supply chain under CSR.