The invention discloses wind load test equipment and a wind load test method for a transmission tower line system under the action of a moving thunderstorm wind. The test device comprises a jet device, wherein the jet device is formed by sequentially connecting a fan section, a diffusion section, a stable section and a contraction section which can change diameter of an outlet. The test device is characterized in that the jet device is equipped with a lifting mechanism which can adjust jet height and a driving mechanism which controls rotation speed of a rotor in a remote manner through a frequency converter, the driving mechanism can drive the jet device arranged on a sliding rail to move along the sliding rail at a specified speed, the jet device, the lifting mechanism and the driving mechanism form a non-steady-state thunderstorm-wind wind field simulation device capable of adjusting the jet height, and the non-steady-state thunderstorm-wind wind field simulation device is combined with a transmission tower rigidity pressure measuring model to form single balance force measurement test of a tower body truncated model and multiple balance force measurement test of the tower line system respectively.