The invention discloses an apparatus used for the ultrasonic detection of the internal manufacturing defects of an automobile hub. The apparatus includes an aluminum frame 1, a water tank 2, a detection platform mechanism 3, a probe detection mechanism 4, a visual positioning mechanism 5, a carrying mechanism 6, an input mechanism 7 and an output mechanism 8; a top mounting plate 11 is arranged onthe aluminum frame 1; the top mounting plate 11 is provided with the visual positioning mechanism 5 and the carrying mechanism 6; a stamping plate 12 is arranged in the middle of the interior of thealuminum frame 1; the water tank 2 is arranged in the middle of the stamping plate 12; the detection platform mechanism 3 is arranged in the water tank 2; and the probe detection mechanism 4 is arranged at the top of the aluminum frame 1. According to the apparatus of the invention, the hub is moved through the carrying mechanism; the visual positioning mechanism and the detection platform can accurately locate the hub; the rotating speed of a motor can be adjusted, so that the rotating speed of the detection platform can be controlled; and detection signals are collected through a fixed probe, so that the most accurate internal detection signals of the hub are obtained, and the accurate detection of the hub can be facilitated..