A repair structure for a liquid crystal display (LCD) panel and a repairing method thereof are disclosed. The LCD panel includes a plurality of common lines being parallel to a plurality of scan lines, and the common lines and the scan lines are alternately disposed on a substrate. Each of the common lines has a plurality of branches and gaps. The branches are parallel to a plurality of signal lines, and the gaps are defined between a trunk of the common lines and the branches. The branches overlap without contacting the signal lines. Each branch, the corresponding signal line and the pixel electrode are arranged so as to expose the corresponding gap. The gap is utilized for providing an external tool to cut off the common line to be disconnected from the branch.