The　sudden　change　of　joint　velocity　in　fault　tolerant　operation　of　two　coordinating　manipulators　for　joint-locking　failures　is　studied.　First,　the　difference　between　the　joint　velocity　of　original　manipulator　and　that　of　reduced　manipulator　is　defined　as　the　sudden　change　in　joint　velocity.　Then,　a　corresponding　fault　tolerant　planning　algorithm　based　on　this　criterion　is　proposed.　At　last,　a　simulation　example　of　fault　tolerant　operations　is　implemented　with　two　planar　3R　manipulators.　Simulation　results　show　that　this　algorithm　can　effectively　avoid　the　sudden　change　of　joint　velocity　occurring　in　fault　tolerant　operation　of　two　coordinating　manipulators,　strengthen　their　motion　stability　and　so　improve　their　kinematical　and　dynamic　properties　in　fault　tolerant　operations.