The invention provides a crossover structure dynamic mechanical test device, including a base, a lead, a lead supporting device, a crossover structure simulation mechanism and multiple strain gauges. The lead supporting device is connected with the base in a position-adjustable manner, two ends of the lead are slidably connected with the lead supporting device, and the lead is in a suspension state. The crossover structure simulation mechanism is connected with the base in a position-adjustable manner and is disposed under the lead. Each strain gauge is arranged in the crossover structure simulation mechanism, and used for testing the deformation amount of the crossover structure simulation mechanism under the impact of the lead when the lead is cut through. Each strain gauge is used for testing the deformation amount of the crossover structure simulation mechanism under the impact of the lead, and the mechanical performance of the crossover structure simulation mechanism is tested by the tested deformation amount, so that corresponding treatment can be conducted for the crossover structure in the actual working condition, thereby improving the safety of the crossover construction. The test device provided by the invention effectively ensures the test accuracy.