The invention provides a main cable system with a dehumidifying corrosion-prevention system of a suspension bridge. The main cable system with the dehumidifying corrosion-prevention system of the suspension bridge comprises a main cable segment, fastening cable clamps, dehumidifying cable clamp assemblies and dehumidifying equipment; the dehumidifying cable clamp assemblies comprise locating assemblies, dehumidifying pieces, sealing pieces and sealing material; in an installation state, the locating pieces are fastened and clamped on the main cable through bolts; each dehumidifying piece is directly installed on the main cable or installed on the main cable through one locating piece; the surfaces of the joints of the locating pieces and the main cable and the surface of the main cable arecoated with bottom corrosion-prevention material, S-shaped protective steel wires are wound around the main cable, and the outer portions of the S-shaped protective steel wires are coated with main-cable sealing corrosion-prevention material; the sealing pieces are connected onto the locating pieces; main-cable corrosion-prevention material is adopted to coat the joint of each portion of each dehumidifying cable clamp assembly and the main cable to prevent corrosion, and the dehumidifying cable clamp assemblies and a main cable system body of the suspension bridge form an air-tight performance structure; by means of the dehumidifying equipment, partial moisture in the main cable is pumped out, so that the phenomenon of main cable corrosion caused by residual moisture in the suspension main cable during an arrangement process and moisture generated in an operation process is avoided.