This study develops a blocked cost model of urban rail transit, which is applied to determine laying mode of urban rail transit. In addition, this model focuses on the laying mode choice of urban rail transit by using quantitative analysis, which is previously discussed by using qualitative analysis. The case of Line No. 1 of Shijiazhuang urban rail transit is given to demonstrate the blocked cost. The results show that the cost of urban rail transit on the ground is 0.372 billion RMB per km and the cost of urban rail transit underground is 1.79 billion RMB per km. The mode on the ground is the best solution due to its low cost. But by analyzing and evaluating generalized cost in which blocked cost has been considered, the mode of urban railway transit underground is the best choice due to 1.79 billion RMB per km compared to 1.91 billion RMB per km on the ground.