Abstract: In this paper, the dynamic behavior of guyed masts is investigated through model tests in a wind tunnel. It is found that: ① A guyed mast has very close natural frequencies and its dynamic responses have the property of broad band; ② As wind speed increases, PSD of responses alter from discrete form to continuous style and large amounts of frequency component emerge. Responses show some chaotic characteristics. Superposition methods are inaccurate in this case and numerical analysis is recommended; ③It is improper for fluctuating displacements to take zero-average assumption under high wind speed conditions. However, on probabilistic problems the Gaussian assumption may still be made provided average is considered; ④ Lateral responses are mainly derived from energy transfer between longitudinal and lateral vibrations. Installations of VED or TSD devices tuned at the 1st and 2nd natural frequencies are suggested.