In order to design and develop novel-spun yarns with good functionality, we investigated how to construct a core-sheath structure adapted from a multilayered structure of triplet- spun yarn and/or made from a twin-spun yarn with core-staple fibers using an experimental ring-spinning frame. The results were follows: (1) staple-core twin-spun yarn, a new yarn, could be made by applying the production method of triplet-spun yarn and/or combining the production methods of core-spun yarn and twin-spun yarn into one twisting process; (2) by adopting three rovings made from fibers of differing length and fineness, the resulting triplet- spun yarn had the core-sheath structure within an adequate spinning condition; (3) for the construction of core-sheath structure, it is important that there be a difference between spinning tensions at the center and the two sides of the drafted fiber strands or drafted strand lengths from the front roller nip to the point of yarn formation by controlling the distance of the supply rovings and the yarn’s twist factor.