Based on the theory of random vibration and system identification, the ambient vibration testing of two Adjacent transmission towers were carried out. The dynamic characteristic of the towers were analyzed and compared. The experimental results show that the first three orders of natural frequency of two adjacent transmission towers are transverse vibration, longitudinal vibration and torsional vibration. The transmission tower adjacent to the angle tower has the same member type and material to the two adjacent tangent transmission towers, but the vibration characteristics of it are influenced by the behavior of the conductors. So wind vibration coefficient of the transmission towers changed, too. The transmission tower around the corner has special location and asymmetric structure, its vibration are torsional vibration and coupled vibration.