The invention discloses a drop-out fuse monitoring and alarming device for a power transformer. The drop-out fuse monitoring and alarming device comprises the components of sensors, monitoring circuits, a central processing unit, indicating lamps, an alarm loudspeaker and an alarm communication module. The sensors sleeve a high-voltage line between a drop-out fuse and the high-voltage side of the power transformer. The sensors are connected with the input end of the central processing unit through the monitoring circuits. The first output end, the second output end and the third output end of the central processing unit are connected with the indicating lamps. The fourth output end of the central processing unit is connected with the alarm loudspeaker. The fifth output end of the central processing unit is connected with the alarm communication module. The drop-out fuse monitoring and alarming device has advantages of reasonable design, simple structure, reliable action and easy manufacture. The drop-out fuse monitoring and alarming device can automatically monitor the operation state of the drop-out fuse. When a fault of the drop-out fuse occurs, the drop-out fuse monitoring and alarming device can automatically perform sound and light alarm and wireless mobile phone short message alarm, thereby reminding personnel to handle the fault in time, and effectively reducing number of electric power using incapability times of a user.