The invention discloses a capacitor protection device, including a capacitor, a special fuse for the capacitor, and a pedestal used for connecting the fuse and the capacitor. The fuse includes a movable fusion tube, a fixed fusion tube and a tension spring used for connecting the movable fusion tube and the pedestal, the capacitor protection device also includes a travel switch arranged in the position of a grounding bolt of the capacitor, a stressed contact of the travel switch is replaced by a lengthened insulating rod, and the top of the stressed contact is slightly higher than a limiting piece on a fuse base and is located on a fusing movement track of the movable fusion tube. The invention also discloses a signal alarm control loop. The capacitor protection device and the signal alarm control loop thereof are sensitive and reliable in signal indication and sound alarm, and successfully solve the problem that fusing of a capacitor fuse wire is not easy to discover or is not discovered in time.