For a two-stage dual-channel supply chain led by manufacturer, the article considers two types of market structures:monopoly and oligopoly in both the upstream manufacturer market and downstream e-commerce platform market. Consequently, four vertical structural models of dual-channel supply chain distribution models are constructed, such as “both upstream and downstream are monopoly （OO type）”, “only upstream is monopoly （MO type）”, “only downstream is monopoly （OM type）” and “both upstream and downstream are duopoly （OO type）”. This paper compares the performance of the above four types of models under market equilibrium conditions using numerical simulation method. The results show that in the supply and sales game with both horizontal and vertical competition between manufacturers and e-commerce platforms, the specific structure of the supply chain has a significant impact on the pricing strategies and profit levels for undifferentiated and homogenized products or services, and both manufacturers and platforms show a strong tendency towards monopoly. However, it is worth noting that the lowest levels of transaction commissions and online prices do not uniformly appear in the most competitive OO-type dual-channel structure, and the highest profits of platforms do not necessarily stem from the OM-type structure with the highest degree of monopoly. This finding challenges the efficiency concept under the competitive structure of a single market segment, provides a new perspective for traditional market structure theory research, and reveals the more complex market interaction mechanism in the dual-channel supply chain.