With the continuous development of industrial robot application, it becomes very important for the solution of reachable space in the designing and applicating process. But the traditional theory calculation method is complex. When solving the reachable space of new kind of robot, we only draw lessons from the theory and need to change more. So a simple and convenient method is needed in theory field. This paper proposes a method that combine Matlab with SimDesigner to solve 6-DOF Robot reachable space, and takes ABB-1400 as an example to explain the solution of 6-DOF Robot reachable space. It could attain the full reachable space by add sine motion function reasonably to every joint, and obtain the solution of robot reachable space speedly.