Abstract: Introduced in the paper is the design of a Φ841 mm cooling bed for large size seamless steel tubes concerning its major technical parameters，composition and cooling schedule.The main difficulties in designing，manufacuturing and assembling the cooling bed as well as its design characteristics are analyzed.Based on the analysis，it is concluded that the Φ841 mm cooling bed for large size seamless steel tubes has complete functions，reasonable design， low cost and high automation level， as well as a comprehensive performance reaching the advanced domestic level， which is realized by design aspects such as double-roller chain claw structure， big gradient arrangement and drive motor reversing device etc.