Inefficient delivery services undermine consumers’ online shopping experience, posing a crucial challenge for e-commerce platforms and suppliers. In a platform-supplier cooperative delivery system, the issue of unclear responsibility for quality defects often arises. By utilizing real-time traceability enabled by blockchain, the platform can promptly identify supplier delivery accidents and return defective products directly to the supplier. This blockchain-enabled return mechanism could significantly reduce disputes in cooperative delivery processes. We develop a game theoretical model to analyze delivery strategies in supply chains with and without blockchain, and further examine the impact of blockchain on members’ delivery services and their profits. Our analysis indicates that blockchain incentivizes the platform to conduct high-level delivery services. However, it may either encourage or discourage the supplier’s provision of high-level delivery services. Moreover, blockchain acts as a double-edged sword in the supply chain, enhancing consumer satisfaction while also increasing wholesale prices. The interaction between these two effects determines whether blockchain negatively impacts on the supply chain’s profit, with the disposal cost of returned products by the supplier playing a crucial role. When the supplier’s disposal cost is relatively high, blockchain may result in supply chain members being worse off, despite its enhancement of consumer satisfaction. Furthermore, we find that blockchain enhances both the delivery service level and the profit of the supply chain if neither the supplier’s disposal cost nor the platform’s cost of high-level service are high. This study provides valuable insights into the potential benefits and challenges associated with blockchain adoption in cooperative delivery systems.