The invention discloses an underground pipe gallery monitoring and water preventing structure based on building informatization. The underground pipe gallery monitoring and water preventing structurecomprises a pipe gallery assembled building block and a controller, wherein an electrical pipeline cavity, an oil-gas pipeline cavity and a comprehensive pipeline cavity are arranged inside the pipe gallery assembled building block; a water collecting and air ventilating cavity is arranged at the bottom of the pipe gallery assembled building block; hydrophilic layers are attached to the upper walls of the electrical pipeline cavity, the oil-gas pipeline cavity and the comprehensive pipeline cavity; a plurality of capillaries are arranged on the hydrophilic layers; and the diameter of each capillary is 2-3 mm. The underground pipe gallery monitoring and water preventing structure has the advantages that through the magnetic field action of permanent magnets in all brackets, all the bracketscan be kept in the balanced state; when water leaks from one position of a pipe gallery, water-absorbing cotton at the corresponding position absorbs the water and conducts electricity, so that a transmitter and an electromagnet at the corresponding position can be conductive; and when the electromagnet is powered on, the magnetic field direction of the electromagnet is opposite to that of the corresponding permanent magnet, so that lamp holders on the upper and lower sides of the corresponding position can move away from the water leakage direction, and then a short circuit and other greaterhazards caused by water leakage can be avoided.