Hybrid　position　and　force　control　problem　of　grasped　object　of　a　free-floating　space　manipulator　with　closed　kinematic　chain　was　discussed.　By　combining　the　relationship　of　the　linear　and　angular　momentum　conversation,　closed　kinematic　chain　restraints　and　multi-body　dynamic　method,　the　synthetical　dynamic　model　of　the　free　floating　space　manipulator　grasping　system　was　established.　With　uncertain　parameters　and　external　disturbance,　an　adaptive　backstepping　neural　network　control　scheme　was　developed　to　track　the　desired　trajectory　of　object,　and　the　correspondent　scheme　of　internal　forces　control　was　proposed　synchronously.　Therefore,　the　object　position　and　internal　force　can　be　regulated　simultaneously.　The　proposed　control　scheme　needs　not　to　linearly　parameterize　the　dynamic　equation　of　the　system.　Meanwhile,　it　can　guarantee　asymptotically　stability　of　the　system.　A　planar　free-floating　space　manipulator　was　simulated　to　verify　that　the　proposed　control　scheme　can　eliminate　the　effect　of　uncertain　parameters　on　the　system.