The invention discloses a method and system for checking island crossing of high-speed lines in locating and wiring. The method comprises the following steps of: calculating an area, on the current wiring layer, of a high-speed line and a mapping area, on a reference layer, of the high-speed line in sequence; if the area, on the current wiring layer, of the high-speed line and the mapping area, onthe reference layer, of the high-speed line are equal, judging that the high-speed line does not cross an island, and otherwise, judging that the high-speed line crosses an island; and adding the island crossing high-speed line into a problem list, wherein the problem list comprises coordinates, layers and names of high-speed lines. The system comprises an area calculation module, a judging module and a problem list establishing module. Through the method and the system, the condition that certain high-speed lines are unchecked can be effectively avoided, and benefit is brought to improve thehigh-speed line island crossing checking correctness and efficiency.