To identify the optimal channel structure in the consumer electronics industry, the issue of channel optimisation was studied in a supply chain with one retailer and one manufacturer. This study discussed how the retailer can effectively sell products through either the online/offline retail channel or both retail channels simultaneously. Three Stackelberg game models were formulated to study these different retail channels. Then, the optimal decisions were derived in closed-form solutions for each channel. To maximize the retailer's profit, the selections of optimal channels for both retailer and manufacturer were compared, respectively, from the aspect of supply chain coordination. The analytical results indicate that the retail structure of dual-channel is the optimal choice for the retailer, which depends on the channel selection of manufacturer and the channel preference and price difference sensitivity of consumer. In addition, both retailer and manufacturer can overcome disagreement by a supply chain contract that combines the wholesale price and compensation plan. This study not only conducts the theoretical analysis for the optimal decisions of retailer channel but also provides managerial implications for the mixed-channel construction of retailers in practice.