Abstract: It is important to reduce the fire spread risk in densely built wood building areas by improving the fire protection level of critical buildings that dominate the extent of fire spread. For this purpose, the paper proposes a methodology to identify the critical buildings based on field-network simulations of multiple fire scenarios. Firstly, the fire spread matrix and adjacency matrix are proposed by directed graph model combing the field-network simulation results; and then the paper defines indices for risk, connectivity and importance of nodes, as well as the expected loss of different fire scenarios. The critical buildings are then determined by comparing all the buildings in terms of their indices. The protection priorities are also determined by considering the effect of fire protection and updating the field-network model. Finally, the proposed method is illustrated in a typical densely built area consisting stilt style wood structures in Yunnan province. The results show that the critical buildings and their fire protection priorities can be accurately determined by the method. With the method, the number of ignited buildings as well as the fire loss can be reduced through improving the fire protection levels of a relatively small number of buildings.