The invention relates to the brake belt technology field and particularly relates to an automatic gearbox brake belt experiment device. A brake belt is sleeved on the outer side of a clutch, a right end of the clutch is connected with a rotation disc, the rotation disc is connected with a positioning disc, a right end of the positioning disc is connected with a rotating shaft of the stand, a fixedsleeve is arranged in a cylindrical shaft of the rotation disc, a left end of a base is provided with a torque sensor, an adapter disc is connected with an oil supply pipeline on the stand, a pistontop rod is in contact with a stopper at one end of the brake belt, an end portion of the piston top rod is provided with a piston body, a return spring is arranged between the piston body and an innerwall of the base, and a brake pressure supply oil path is connected between a piston cover inside a piston cavity and the piston body through a tee pipe. Clutch hub, clutch, brake pressure supply oiland lubricating oil work conditions can be simulated, interference factors caused by parts in an integral machine experiment are eliminated, and an influence problem caused by the interference factors of other parts during brake belt experiments can be solved.