The invention provides a telescopic seam waterproof structure of a cable tunnel and the cable tunnel. The telescopic seam waterproof structure is characterized in that closed water-stop belts are vertically arranged inside side plates of two adjacent cable tunnel sections by virtue of side plate water-stop belt fixing devices; the closed water-stop belts are arranged in a peviform which is concave towards the top surface of a bottom plate or a top plate inside the bottom plate and top plate of two adjacent cable tunnel sections by virtue of bottom plate water-stop belt fixing devices and top plate water-stop belt fixing devices, so that the telescopic seam waterproof structure conforms to deformation direction of the closed water-stop belts in a sleeving process, and the difficulty in installing and fixing the water-stop belts in a cable tunnel construction process is reduced. In addition, the closed water-stop belts are arranged in the peviform which is concave towards the top surface of the bottom plate or the top plate inside the bottom plate and top plate of the two adjacent cable tunnel sections, so that vibration compacting during a later-period concrete pouring process is facilitated, poured concrete is large in density, free from bubbles and free from pulp leakage, and the waterproof performance of the cable tunnel is further improved.