The invention provides a device for detecting accident vehicle braking performance and belongs to the technical field of automobile braking performance detection devices. The device comprises a mechanical part and an electrical control part. The mechanical part comprises a pedestal, a supporting device, an electromotor, a speed reducer, a buffer device, a rigid transmission shaft, claw-type chuck assembly, a lifting device, a disc-type torque sensor and a weighting sensor; the electrical control part comprises a computer, a one-chip microcomputer, a detection indicating device and a printer. The claw-type chuck assembly and a rotating part inside the torque sensor rotate about an axis. The torque sensor converts the force which is conveyed by a claw-type rod piece and is proportional to the braking force in to electric signals and transfers the electric signal to the one-chip microcomputer. The device is convenient for disassembly and assembly, easy to operate, and is portable. By means of the device, braking performance of accident vehicles can be directly detected on-site to avoid a waste of time due to towing the accident vehicles to a check station so that detection efficiency is greatly increased and it is easy to realize.