In　this　article,　an　image-based　visual　servoing　(IBVS)　control　strategy　is　proposed　for　the　unmanned　aerial　manipulator　(UAM)　system　to　track　and　grasp　a　moving　target.　Specifically,　a　robust-adaptive　velocity　observer　is　designed　to　estimate　the　relative　velocity　between　the　tracked　target　and　the　UAM　platform.　Based　on　the　velocity　observer,　an　IBVS　controller　using　onboard　camera　of　the　UAM　platform　is　proposed　for　moving　target　tracking　without　velocity　measurement.　Then,　the　barrier　Lyapunov　function　is　introduced　into　the　UAM　platform　IBVS　controller　to　ensure　the　safety　of　target　tracking.　Besides,　another　virtual　camera　is　constructed　on　manipulator　end-effector　to　compensate　for　the　tracking　error　of　the　UAM　platform.　As　a　benefit,　the　eye-to-hand　onboard　camera　ensures　the　global　view　of　the　UAM,　and　the　eye-in-hand　virtual　camera　of　the　manipulator　ensures　the　accuracy　of　the　grasping　task.　Finally,　the　stability　of　the　proposed　IBVS　control　strategy　is　analyzed　through　Lyapunov　theory.　The　comparative　simulations　are　provided　to　illustrate　the　target　tracking　performance　of　the　proposed　method.　The　experimental　results　demonstrate　that　the　proposed　method　can　be　applied　to　the　UAM　with　a　low-cost　sensor　suite　to　realize　the　tasks　of　tracking　and　grasping　a　moving　target.