The invention provides a multi-laser radar array monitoring method for an overhead transmission line. A multi-laser radar array comprises an optical lens set, a laser emitting and receiving system and a data processing system. The multi-laser radar array is adopted for performing layering scanning on the space under a high-voltage power line of the overhead transmission line and monitoring if the objects, including people, vehicles, plants, and the like, which are possible to result in the damage to the overhead transmission line, exist in the space nearby the overhead transmission line. The multi-laser radar array is adopted for performing three-dimensional scanning on the surrounding space of the overhead transmission line; when foreign objects invade into the space nearby the overhead transmission line, the multi-laser radar array can immediately monitor the invading objects and can accurately monitor the practical appearance and size of the invading objects and the practical distance from the transmission line to the invading objects, so that the instantaneity and accuracy of monitoring for the foreign objects invading to the overhead transmission line can be guaranteed; and the real-time data is fed back to an intelligent analysis system, so that the real-time early warning function for the foreign objects invading to the overhead transmission line can be achieved.