Abstract: Because of the special position of tunnel vault, conventional water drill can′ t safely and effectively carry out coring. An intelligent device for coring at tunnel vault was developed, which eliminates the risks of motor burning and electric leakage caused by cooling water reflux. The device can intelligently identify the position of waterproof board to avoid the risk of breaking of waterproof board; in the process of coring, the compactness, strength and homogeneity of lining concrete are predicted based on the changes of coring speed and electric current of drilling rig;through coring, the thickness and void depth of lining at tunnel vault can be detected. Finally a kind of core hole repairing technology was proposed.