The utility model relates to a fastening component for rail theft protection and rust protection, comprising a nut, a gasket, a waterproof cover and a screw. Threads matching the screw are prepared in the internal hole of the screw; the periphery of the nut is in a shape with odd uniform edges (more than 5 edges); the gasket is a cylindrical gasket, and the through hole in the middle of the cylindrical gasket matches the screw; the end face of the cylindrical gasket wall is 15-20mm higher than the end face of the nut; the nut is arranged in the gasket and connected onto the screw by spiral connection, and the distance between the excircle of the peripheral edges of the nut and the inner ring of the cylindrical gasket wall is 3-10mm, and a waterproof cover with an opening provided at the bottom is fastened on the outer ring of the cylindrical gasket wall. The utility model is characterized in a simple structure, low production cost; anti-theft, rust-protection and dust-prevention functions are provided, and the service life of the fastening component is increased.