The invention relates to the internal hole detection field, and discloses a hole detection system and a hole detection method, which are used to realize hole system coaxality detection. The hole detection system comprises a support, a telescoping rod, a distance detection element, and a controller. The distance detection element is disposed on one end of the telescopic rod, and the other end of the telescopic rod is rotatably connected with the support. The distance detection element is electrically connected with the controller, and the controller is used to calculate a circle center position of a detected work piece according to a distance detected by the distance detection element. By adopting the technical scheme, the hole system coaxality detection is simpler, and during a hole processing process, the detected hole system coaxality is timely fed back to the processing process, and therefore product quality is improved.