Retractable roof becomes popular in recent years because it can make the roof close, open or partly open to meet different purpose. The roof status can be changed according to climate condition outside. It can make people inside feel more comfortable and save energy sometimes. Mechanical system of retractable roof plays a very important role in system safety and reliability. With the experience of retractable roof of Kunshan indoor stadium, design of mechanical driving and supporting system is introduced. Calculation method for key parts and limitation for architecture structure are provided. This paper provides helpful reference for design of mechanical system on retractable roof.