We analyze a transaction mechanism so-called the revenue sharing transaction model and its dynamics in a supply chain with two competing suppliers and a monopolistic retailer when the demand pattern is uncertain and the back-order is allowed in case. We assume that the products by the suppliers are substitutable each other with a certain degree even though their retail prices are different. It is proved that a supplier and the retailer in the supply chain have some room for enjoying the possibility of their increased profits comparing with the present ones by adopting the suggested revenue sharing scheme. Furthermore, such a transaction model is beneficial even to the customers by offering a lower retail price than before. On the contrary, we observe that another supplier which sticks to an existing transaction scheme is supposed to suffer some decrease in its profit as a result.