The utility model discloses a stride across power transmission line block a river cable greatly, including two leap towers that are located two river banks respectively, line between two leap tower centers is perpendicular with the river course, it closes the floodgate to be located one of them hank of subaerial fixed mounting of strideing across tower one side, the top of the tower and the body of the tower department of two leap towers all are equipped with the standing block, it is equipped with a subsidiary hoist cable and main hoist cable to stride across the tower, the both ends of assisting the hoist cable are fixed with two river banks respectively, and it locates on the standing block on two leap tata tops to assist the all alone stature of hoist cable, the one end and the hank of main hoist cable close the floodgate to be connected, the other end of main hoist cable is fixed with another river bank, and the all alone stature of main hoist cable is located on the standing block of two leap tata bodies, the utility model discloses can effectual messenger adopt the speed reduction of sand ship to protection transmission line.