Abstract: This paper builds the model that can show the broken zone in soft rock roads on the base of ANSYS. The stress-distributing diagram can be given after inputting the reasonable parameters and limited conditions to the model and calculating. Stress can be given through setting paths in the stress-distributing diagram and the range of the broken zone can be judged. The engineering application example shows the average error between the given data out of the model and the ones out of the test are low.