The invention relates to a high-speed train gearbox no-load running-in test bench, which is composed of a driving device, axle end transition bearing positioning clamping devices, a large-span mobile wheel set axle positioning supporting device, a gearbox input end pressing vertical column device and a noise testing device, wherein the driving device is arranged at the left end of a test bench base (1); a fixing-end and a mobile-end transition bearing positioning clamping devices are arranged at the left side and the right side of the test bench base (1) respectively; the large-span mobile wheel set axle positioning supporting device is composed of two sets of large-span mobile wheel set axle positioning supporting devices with the same structure; the gearbox input end pressing vertical column device is arranged on the test bench base (1); and the noise testing device comprises noise testing sound level meters and supporting tube assemblies arranged at the input end and the output end of the gearbox respectively. A series of technical problems that the existing gearbox no-load running-in test bench is complicated to assemble and disassemble, an axle journal is damaged, a high rotation speed can not be met and the like can be solved.