Base on Krugman¡¦s NEG model, we subsume urban cost in this study. Referring to study procedure of Murata and Thisse, make few changes of the model. Then, we get 3 conclusions of this study: (1) Due to the difference between commuting costs of each region, the symmetric distribution of workers will no longer make the largest total mass of varieties. While a region attend to traffic construction in order to drop people¡¦s commuting cost, agglomeration economic will not certainly make a negative impact on urban cost or effect people¡¦s variety consumption behavior. (2) In the case of an agglomeration, if the transportation costs are sufficiently large, the agglomeration equilibrium will be stable. The larger the transportation costs between regions, the larger cost of consuming other regions¡¦ commodity. Thus, chose to agglomerate in a bigger region can get cheaper and variety manufacturing commodities easily. And the agglomeration equilibrium will be stable. (3) Any change of commuting cost of the other region will not influence the stable of agglomeration equilibrium.