The present invention provides an autonomous robot and a device and method for fault detection, belonging to the robot field. The method comprises: when a plurality of first distances detected by a proximity detector are smaller than a first presetting threshold, controlling an autonomous robot to perform spinning on the spot; obtaining a plurality of distances detected by the proximity detector in the spinning process; and determining whether the proximity detector has faults or not based on the second distances and the second presetting threshold. In the process of the spinning of the autonomous robot, the proximity detector is used to detect the distance between the autonomous robot and the barrier in various directions to determine the surrounding of the autonomous robot, and autonomous robot and the device and method for fault detection determine whether the proximity detector has faults or not based on the second distances and the second presetting threshold to avoid that the autonomous robot detects the fault when the proximity detector is shielded by a barrier or close to a barrier at some direction so as to allow the accuracy of the fault detection to be higher through the autonomous robot.