The invention relates to a seven-degree-of-freedom robot, and belongs to the technical field of robots. The seven-degree-of-freedom robot comprises a mechanical arm and a probe, wherein a main body structure of the mechanical arm comprises a base, a waist column, a large arm, a small arm, a first wrist part, a second wrist part, a third wrist part and a fourth wrist part, which are connected in sequence through joints; and the joints can be rotated around corresponding rotating planes H. The seven-degree-of-freedom robot can be used for maintenance of such machinery as a rail vehicle steeringframe in a narrow range.