Belonging to the technical field of ultrasonic detection, the invention in particular relates to a floating nuclear reactor internals baffle bolt inspection device. The inspection device has the characteristics of compact structure, convenient transportation, lifting and operation, low requirements for the motion performance of a floating apparatus, low requirements for the operation skills of thestaff, and high inspection efficiency. The invention guarantees that two sides are always fitted with baffles through roll balls when the device works, so that the detection can be based on two sides, thus improving the detection efficiency. The probe involved in the detection device can move transversely, move forward and backward and rotate, the transverse movement of the probe can send the probe to the transverse position of a detected object, the forward and backward stretching of the probe can send the probe to the top of the detected object, rotation of the probe can make the angle of the probe coincide with the that of the detected object, thereby further improving the detection efficiency.