The simulation of support settlement of a transmission angle-tower is actively carried out in this study based on the actual structural damage events. The mechanical model of the transmission angle-tower is developed based on the spatial member finite element approach. The finite element model of the transmission tower-line system is constructed by taking a real 220KV transmission tower as an example. The support settlement of the tower is analyzed and the collected information are utilized in the structural finite element analysis. The made observations indicate that the support settlement may induce large structural internal forces, which may induce potential disk to the structural safety.