In the conditions of Rain-wind excitation, droplets suspended to the conductor within the strong electric field, which amplifies corona discharge and generate ionic wind. The ionic wind coupling with wind force induced vibration of the cable, which seriously affected the cable's normal operation of transmission and stability. Study on mechanism of corona discharge excitation, a finite element model of Rain-wind vibration is established based on the finite element theory and the Newmark algorithm. Take LGJ-240 as an instance, using experimental and numerical analysis to analyze the impact on amplitude of cable by the air humidity and density, conductor surface conditions, cable structure factors and tensions. Methods and conclusions in this paper can be used as references for designing UHV transmission liens, upgrading the existing lines and controlling vibration.