The invention belongs to the technical field of 
water supply, and discloses an automatic 
water supply device for building projects. The device comprises a water cabin, wherein a 
silicon battery panel is laid on the top of the water cabin; a 
water supply pipe is arranged at the right end of the water cabin; a 
water level alarm apparatus is embedded into the bottom of the right end of the water cabin; an underground 
pipe is arranged at the bottom of the water cabin; a 
machine case is fixed in the water cabin via a bolt; an energy accumulator is fixed on the left side of the 
machine case via a bolt; a 
water level monitor is embedded into the top of the 
machine case; a controller is arranged on the right side of the machine case; a water pump is fixed to the lower part of the machine case via a bolt; a water drain 
pipe is joined with the right end of the water pump; the underground pipe is joined with the bottom of the water pump; the 
silicon battery panel is connected with the energy accumulator via an electric circuit; and the energy accumulator, the 
water level monitor, the controller and the water pump are connected via the electric circuit. According to the device provided by the invention, the 
silicon battery panel is arranged, so that efficient 
clean energy can be provided, and the device is energy-saving, economical and 
environmentally friendly; the water level alarm apparatus is arranged, so that too low water level can be alarmed in advance, and a construction period is prevented from being influenced by untimely water supply; the device is simple to construct, convenient and practical.