Abstract: Joint procurement has become an important application model along with the rapid development of collaborative B-to-B electronic commerce.The success of such model requires the active participation of all the supply chain members,including the sellers and buyers.In this paper,we deliberately analyze the benefits of joint procurement employed by two buyers and compare all members’ participating motivation and corresponding total purchasing cost with the sellers’ two different wholesale pricing policies.We conclude regularly that the buyers have the motivation to purchase jointly as long as coordination cost is low enough,and there exists a critical coordination cost threshold for joint procurement without respect to the seller’s wholesale pricing policies,consisting of fixed wholesale pricing policy and quantity discounts policy.When the coordination cost is imposed less than that critical threshold,buyers’ joint procurement will simultaneously spare the annual purchasing cost for the sellers and buyers.On the other hand,either supply chain members will take negative cost margin definitely.

Key words: electronic commerce, joint procurement, coordination cost