The invention provides a long cylinder barrel inner cavity cleaning machine. The long cylinder barrel inner cavity cleaning machine comprises a rack, a probe, a probe feeding device, a probe rotating device, a lifting positioning device, a tightly compressing device and a supporting roller device, the probe is fixed at the front end of the rack, the probe feeding device is fixed at the end of the probe, the supporting roller device is fixed at the middle end of the probe, the probe rotating device is fixed at the tail end of the probe, the lifting positioning device is fixed on the rear section of the rack, and the tightly compressing device is fixed on a table-board on the rear section of the rack. According to the long cylinder barrel inner cavity cleaning machine, when a cylinder barrel inner cavity is cleaned, the cleanliness of the cleaned cylinder barrel inner cavity can be improved and guaranteed, a cylinder barrel and the probe are concentric by the aid of mechanical aligning of a lifting speed reducer and a walking speed reducer, the probe of the long cylinder barrel inner cavity cleaning machine can be effectively prevented from deforming, the probe and a hairbrush can be effectively protected from being damaged, a workpiece can be prevented from shaking when the probe violently rotates, the manual cleaning is replaced by the cylinder barrel inner cavity cleaning machine, the cleaning efficiency is effectively improved, and the labor intensity of workers is reduced.