For a supply chain with two suppliers and a buyer, this paper studies the impact of the deferred payment strategy and the blockchain+deferred payment strategy on supply chain quality management,taking supplier adulteration into account, by constructing a principal-agent model in which the buyer acts as the leader under asymmetric information. Specifically, by comparing the equilibrium results under the deferred payment strategy and the blockchain + deferred payment strategy, this paper analyzes the impacts of factors such as the supplier’s adulteration motivations and the probability of adulteration being discovered on buyer’s decisions and supply chain profits, and reveals the value of blockchain technology in supply chain quality management as well as the incentives for supply chain members to adopt it. The result suggests that, under deferred payment strategy, the buyer needs to make three different optimal policies according to the marginal probability of the adulterated product being found by customers. However, under the blockchain+deferred payment strategy, the buyer’s optimal policy is unique due to traceability. Though adopting blockchain can reduce the complexity of buyer’s quality management, it may not necessarily increase the profits of both the buyer and the supply chain. When the supplier’s motivation for adulteration is high, or the probability that two suppliers adulterate at the same time is detected by consumers is low, the buyer is more inclined to adopt blockchain. Compared to the traditional deferred payment strategy, the blockchain + deferred payment strategy may reduce the supplier’s profit or leave it unchanged. Therefore, under certain conditions, the buyer should improve the supplier’s profits through transfer payments to achieve supply chain coordination.