Abstract: To study the influencing factors of bargaining power of supply chain members and the effect mechanism,we have established a game model between the upstream and downstream members of a supply chain under the threat of exit.The equilibrium solution of the model reveals the influence of swit ching cost to the strategy choice of supply chain members.At the same time,through the model conclusion and the mathematical definition of bargaining power,we conclude that the bargaining power of supply chain members is a decreasing functionof their switching cost.Futhermore,we present the internal mechanism of the effect of marker share,information,study ability and degrees of to lerance on the bargaining power of supply chain members.

Key words: switching cost, bargaining power, game model, market share, information, study ability, degree of tolerance.