This study examines the ability of contracts as one of the supply chain coordination mechanisms under competitive conditions. In this study, a two-tier supply chain model with two manufacturers and two retailers is considered to develop a competitive structure when demands are uncertain. The supply chain demand is random and depends on the price of the products. Moreover, the products manufactured by market manufacturers are replaceable. Therefore, the main competitive factor is the order decisions, and due to the nature of the demand, deciding on pricing and ordering is necessary. Each retailer is faced with the issue of determining the prices of goods from two manufacturers, which consequently forms a competitive ground between retailers. Therefore, the two-tiered supply chain model is based on the contract price and is optimized, followed by coordinated analysis. The result of the study shows that to maintain the structure of the supply chain, the manufacturer can increase its wholesale price to the extent that the retailer has zero profit. The lowest price of wholesalers is equal to the cost of production, and the wholesale price can be increased to the point where the retailer's profit is zero.