The present invention relates to a precast pile inclination real-time monitoring and alarm apparatus, which comprises a cabinet and a suspending hook, wherein a connection rod is fixed on the upper portion inside the cabinet, the lower portion is provided with a center shaft disc, a special-shaped rod is connected with the center shaft disc and the connection rod, can rotate along the center axis, and is bound with a heavy hammer through a heavy hammer line, a mercury tank is fixed on the special-shaped rod, and an electrical apparatus box is fixed on the mercury tank. According to the present invention, when a precast pile inclines, the heavy hammer moves toward an inclined vertical plane of the precast pile under a gravity effect to drive the mercury tank fixed on the special-shaped rod to move toward the vertical plane; when a mercury tank inclination angle is equal to or more than a designed angle alpha, long copper wires and short copper wires in the mercury tank immerse into mercury, such that an alarm circuit is turned on, and an alarm alarms so as to prompt inclination state generation; and a flashing light flashes, and a direction of the flashing light can be observed so as to know an inclination direction of the precast pile. The apparatus has the following characteristics that: a structure is simple, the apparatus can be installed on the outer portion of the precast pile so as to easily achieve project construction, precast pile construction can be real-timely monitored and guided, and the apparatus can be reused so as to save construction cost.