Abstract: In this paper, the basic concept of parametric design technology is described, and the design method of prestressed tendons is analyzed. Then based on the above work, parameterization models for the design of prestressed tendons in longitudinal and sectional directions are established, and the ways of accomplishment of the parametric design in the prestressed tendon CAD system are discussed in detail. Compared with traditional CAD systems, this system is more convenient for designers to express their ideas, and has higher efficiency.