The aim of this study was to analyze the effect of fairness concern (FC) and corporate social responsibility (CSR) on the quality improvement of the agricultural product supply chain (APSC) composed of an agricultural product processor (processor) and an agricultural product supermarket (supermarket) so as to ensure the stable supply of high-quality agricultural products. This paper considered both FC and CSR, established four Stackelberg game models, and obtained the effects of FC and CSR on bilateral quality efforts in APSC through comparative analysis and numerical analysis. We prove that the supermarket’s FC can take the role of “profit distribution mechanism”, but it is not conducive to improving all bilateral quality efforts, the utility of the whole supply chain system, and consumer surplus. Additionally, APSC members sharing CSR can not only both improve the quality of agricultural products and promote the expansion of market demand, but they also can improve both the profit of all members and the supply chain. The CSR shared by both members has a greater impact on bilateral quality efforts than the supermarket’s FC, and thus the positive effect of CSR can overcome the negative effect of the supermarket’s FC.