The utility model discloses a lower beam anti -falling device in climbers mode, include the left and right locking piece group of holding tightly, the left and right locking piece group of holding tightly constitutes by the three locking piece of holding tightly, and locking piece hinged joint is passed through to same adjacent holding tightly of holding tightly in the locking piece group between the locking piece, and left and right holding tightly is connected through preceding, back lead screw adjusting device between the locking piece group, lead screw adjusting device includes left lead screw, right lead screw, the screw thread opposite direction of left lead screw, right lead screw, left lead screw, right lead screw all with ratchet adjustment handle's adjusting nut threaded connection, through ratchet adjustment handle's rotation, drive left lead screw, right lead screw, make the left and right locking piece group of holding tightly hold tightly or loosen the wire pole, organize the fixed orifices that sets up the flat insurance area at the left and right locking piece of holding tightly. The utility model discloses rational in infrastructure, the lower beam prevents that the person falls, improves personnel's operation security, guarantees enterprise's safety in production in the realization climbers mode.