At present, many research works focus on modeling trees and simulating the motion of trees in the wind. However, less work has been done in the representation of branch breaking and flying under the strong wind. The mechanism for branch breaking is discussed, and a branch breaking model is built. The motion of the broken branch can be divided into two phases. In the first phase, the broken branch is attached to the trunk. The motion of the broken branch can be considered as a rotation around the attached point. In the second phase, the broken branch begins falling down from the tree. Its motion can be considered as the integration of the rigid body falling under the force acting on the broken branch and rotation around its own. The force analysis is done, and the motion model for the broken branch is built. The stochastic characteristic of branch's movement is taken into account in the model. Based on the model, a system is developed, and different simulation results can be obtained by adjusting the parameters in the model. Experiments show that the simulation results are realistic.