A bullet train gauge-changing bogie for a railway vehicle, comprising a frame, the frame comprising a pair of side beams disposed in parallel and a pair of cross beams connected between the two side beams , wherein a gauge-changing wheelset is respectively disposed at exterior sides of the pair of the cross beams, the wheels of the gauge-changing wheelset are mounted with wheel-mounted brake discs ; each of the side beams or each of the cross beams is mounted with a mounting seat and a brake clamp , and the brake clamp is connected with the mounting seat by support pins ; the support pins are horizontally disposed below the mounting seat , and both ends thereof are fixedly connected with the mounting seat , one end of the brake clamp is provided with a connecting sleeve; the connecting sleeve is firmly sleeved with damping inner sleeves with elastic damping; the connecting sleeve is locked on the support pins through the damping inner sleeves ; when the gauge is changing, the wheel-mounted brake disc on the wheel exerts a thrust on the brake clamp ; when the thrust on the connecting sleeve is greater than the damping force between the connecting sleeve and the support pins , the connecting sleeve drives the brake clamp to move along the support pins , wherein the gauge-changing wheelset includes an axle , wheels and locking mechanisms; characterized in that both ends of the pairs of side beams are respectively provided with an axle-box body , wherein both ends of the axle extend into an axle-box body , respectively, and the wheels are installed on the axle and connected with the axles through splines; in that the locking mechanisms are respectively provided on exterior sides of the wheels and located in an axle-box body at both ends of the axle ; and the locking mechanisms are connected with the wheels , and configured to lock and unlock the wheels to change a gauge of the wheels . a gauge-changing wheelset is respectively disposed at exterior sides of the pair of the cross beams, the wheels of the gauge-changing wheelset are mounted with wheel-mounted brake discs ; each of the side beams or each of the cross beams is mounted with a mounting seat and a brake clamp , and the brake clamp is connected with the mounting seat by support pins ; the support pins are horizontally disposed below the mounting seat , and both ends thereof are fixedly connected with the mounting seat , one end of the brake clamp is provided with a connecting sleeve; the connecting sleeve is firmly sleeved with damping inner sleeves with elastic damping; the connecting sleeve is locked on the support pins through the damping inner sleeves ; when the gauge is changing, the wheel-mounted brake disc on the wheel exerts a thrust on the brake clamp ; when the thrust on the connecting sleeve is greater than the damping force between the connecting sleeve and the support pins , the connecting sleeve drives the brake clamp to move along the support pins , wherein the gauge-changing wheelset includes an axle , wheels and locking mechanisms; characterized in that both ends of the pairs of side beams are respectively provided with an axle-box body , wherein both ends of the axle extend into an axle-box body , respectively, and the wheels are installed on the axle and connected with the axles through splines; in that the locking mechanisms are respectively provided on exterior sides of the wheels and located in an axle-box body at both ends of the axle ; and the locking mechanisms are connected with the wheels , and configured to lock and unlock the wheels to change a gauge of the wheels . <EOS>