The invention discloses a designing system for ship body segmental robot rust-removing and paint-spraying construction. A segmental coating production designing system is connected via a network and asegmental rust-removing and coating CAD graph is input, so a robot trolley XYZ movement path planning design can be finished; then a proper segmental coating robot path platform tool design is selected according to the robot trolley XYZ movement path planning design and a database, so a robot path platform tool design graph is completed; according to practical conditions of a segmental coating workshop, segmental coating construction demands and a scaffold part graph base, a combined scaffold is designed and a segmental coating scaffold part design graph is completed; segmental coating robotpath platform tool manufacturing and installation and the segmental coating scaffold combination and installation can be finished according to the robot trolley XYZ movement path planning design, therobot path platform tool design graph and the segmental coating scaffold part design graph. By the use of the designing system, spraying paint-spraying efficiency can be improved; and damages to construction workers by paint-spraying material can be reduced to a certain degree.