In　order　to　reduce　the　sudden　change,　improve　the　motion　stability　of　the　manipulator　and　increase　its　operational　accuracy　in　fault　tolerance,　this　paper　defines　the　sudden　change　in　joint　velocity　as　an　index　and　a　corresponding　fault　tolerant　planning　algorithm　based　on　this　index　is　proposed.　Then　an　experiment　platform　is　built　up　with　a　PowerCube　manipulator　and　an　Optotrak　motion　measurement　system.　And　the　trajectory　error　of　the　manipulator＇s　end-effector　caused　by　the　sudden　change　is　detected　with　this　platform.　Simulation　results　show　that　the　sudden　change　in　joint　velocity　does　occur　when　a　redundant　manipulator　perform　a　fault　tolerant　operation　for　locked　joint　failures.　The　algorithm　proposed　here　can　effectively　minimize　the　sudden　change.