The invention discloses a cable connecting device in an optimized structure. The device comprises a left clamping member and a right clamping member which are in the arc shapes, left support plates orright support plates are formed at two ends of the left clamping member or the right clamping member, and the left support plates of the left clamping member and the right support plates of the rightclamping member are fixedly connected through stud assemblies. The device is characterized in that a V-shaped clamping block is inserted into the left clamping member, first protruding strips are formed on two end surfaces of the clamping block close to an inner wall of the left clamping member, a plurality of annular first inserting holes are formed on the first protruding strips, annular secondinserting holes opposite to the first inserting holes of the first protruding strips are formed on the inner wall of the left clamping member, one ends of first springs are fixed in the first inserting holes of the first protruding strips in an inserted manner, and the other ends of the first springs are fixed in the second inserting holes of the left clamping member in an inserted manner. According to the device, the problems of sliding and relative rotation of cables can be solved, the fixing of the cables with various dimensions can be realized, and the cables do not need to be specially made.