Abstract: In order to identify tornado-induced wind load characteristics of long-span bridges and the main influencing experimental factors, surface pressure distributions over the deck as well as aerodynamic coefficients were determined through rigid model wind pressure measurements in a tornado vortex simulator. In the experiments, similarity parameters including swirl ratio and aspect ratio were considered. Significant differences are observed between experimental wind loads in the tornado vortex simulator and in the conventional boundary layer wind tunnel. The influence of aspect ratio on the tornado-induced wind loads is much greater than that on the tornadic wind fields, and the degree of the influence is dependent on swirl ratio. According to the results, aspect ratio and swirl ratio are two key similarity parameters in the determination of tornado-induced wind loads on long-span bridges. The experimental findings can provide basic aerodynamic coefficients for tornado-resistant designs on long-span bridges.