The invention discloses a safety street lamp capable of automatically regulating an illumination state on rainy days. The safety street lamp comprises a shell, a water collection tank, a driving box,a lamp post, a driving block, a reserved block, a water outlet and a reserved groove; a mounting bottom plate is welded to and fixed at the bottom end of the lamp post, and a lamp pole is welded to and fixed at the top end of the lamp post; racks are uniformly fixed on one side of the lamp pole, and a shell is arranged on one side of the lamp pole; a second gear is fixed at one inner end of the shell, and a second linkage rod is mounted at the central position of the second gear; a steel wire rope is arranged on a first fixed pulley; the other end of the steel wire rope passes through a secondfixed pulley to be connected with the shell. According to the safety street lamp disclosed by the invention, by mounting the lamp pole, the first fixed pulley, the second fixed pulley, the steel wirerope, a clump weight, the racks, the first gear, the shell, the driving box, the water collection tank and an LED lamp main body, an illumination height of the device can be automatically changed onrainy days, so that the illumination quality is ensured and a traffic accident is avoided.