A variable-section design for hyper-redundant robots is proposed in this paper. In industrial development, especially in the aerospace industry, nuclear industry, and medical field, where traditional rigid linkage robots are not sufficiently adapted to the working environment such as narrow and complex space and high-risk working space, and the stiffness of hyper-redundant robots with equal cross-section is insufficient. In aim to solve this problem, a hyper-redundant robot using variable cross-section design method and decoupled motion control method is proposed in this paper. The simulation results show that the variable section design has good mechanical properties and the trajectory planning meets the requirements. A prototype machine was manufactured to verify its design. Equipped with a nozzle at the end of the robot and completed disinfection operations, shows the robot was capable of completing various tasks as a platform. The research results will provide a new theoretical basis for the design of hyper-redundancy.