The utility model relates to a prevent street lamps and lanterns that falls, innovation point lying in that casing internally mounted has a locking device, and this locking device is including long hoop hasp and locking chain, and screw demountable installation is passed through on the circuit board to locking chain one end, and the other end is locked at long hoop through screw demountable installation. The utility model has the advantage of scientific and reasonable design, simple structure, installation easy maintenance, hasp and circuit joining of plates mode can also the free choice length be bound round to the quantity that can add screw and chain during the use as required, effectively link circuit board and long hoop hasp, avoid lamps and lanterns upper portion directly to fall, safely effectively, and the safety of assurance pedestrian and property, and low cost, the practicality is strong, is applicable to to widely popularize the use.