This paper studies the supply chain system composed of online brand owners based on pure network sales to offline expansion, takes the single network channel model, establishes two dual-channel structure models of offline direct selling model and offline distribution model, and compares and analyzes the influence of different channel structures on the pricing, demand and optimal profit of supply chain members. Research shows that online brands in the offline sales development strategy choice and open offline stores fixed cost and consumer channel preference, when open offline stores fixed cost is very low, or when the fixed cost centered and consumer offline channel preference over a certain threshold, the optimal strategy for offline direct sales model, otherwise for offline distribution model. In order to improve the cooperation efficiency of the supply chain members in the offline distribution model, a bilateral contract mechanism is designed to coordinate the supply chain. When the fixed transfer payment fee is within a certain range, the mechanism can optimize the members of the supply chain and the overall profit.