The purpose of this paper to discuss the monopoly and duopoly firm¡¦s pricing model and the optimal location choice in the Barbell Model. In this study, the first part of this article is that the assumption of market for a barbell market, the monopolist in the face of symmetric and asymmetric barbell market, firm in considering the case of the transportation costs to adopt a different pricing strategy to its optimal location choice. The latter part of this article is to consider if the same circumstances, to a duopoly market, the Cournot and Bertrand competition, the two plants how to choose the most suitable location choice. Also, we discuss the social welfare analysis under different circumstances and when it will reach the principle of minimum differential, or the principle of maximum differential.