Blockchain technology is introduced into the dual-channel supply chain system of online direct marketing and offline traditional retailing to solve the problem of opaque product sources and information asymmetry while also considering consumers' privacy concerns to increase their willingness to buy and improve enterprises' profitability. Based on the introduction of blockchain technology, the paper considers consumers' privacy concerns, uses the manufacturer-dominated Stackelberg game model to solve the equilibrium, and compares and analyzes the optimal pricing decisions and profits of supply chain members in different models before and after the introduction of blockchain technology. It is shown that when blockchain is not adopted, the rise in consumer sensitivity to false appraisal results leads to lower prices, and demand and pricing increase with the probability of the product being genuine; when blockchain is adopted, the increase in privacy concern costs will lead to lower demand and prices. Under a given condition, introducing blockchain technology can enhance the profits of all parties in the supply chain.