This　paper　develops　a　novel　homography-based　visual　servo　control　method　for　the　vertical　take-off　and　landing　(VTOL)　unmanned　aerial　vehicle　(UAV)　tracking　the　trajectory　of　a　6　degrees　of　freedom　(6-DOF)　moving　ship.　Different　from　the　classical　homography-based　visual　servoing　which　is　only　suitable　for　the　trajectory　tracking　of　a　planar　moving　target,　an　extended　homography-based　visual　servoing　framework　is　proposed　to　track　the　trajectory　of　a　6-DOF　moving　target　regardless　of　its　time-varying　rotational　motion.　Taking　entries　in　the　homography　matrix　as　feedback,　the　visual　dynamics　of　UAV　is　established　and　decoupled　into　a　translational　motion　sub-dynamics　and　an　attitude　sub-dynamics　based　on　the　hierarchical　control　strategy.　In　the　translational　motion　subsystem,　the　robust　controller　is　designed　by　embedding　the　nonlinear　differentiator,　the　adaptive　method,　and　a　smooth　saturation　model　in　the　backstepping　control　scheme.　The　saturation　model　is　introduced　to　generate　the　constrained　control　inputs　to　ensure　the　nonsingular　attitude　extraction　and　help　the　visual　points　remain　in　the　camera＇s　field　of　view　(FoV)　simultaneously.　In　the　attitude　subsystem,　a　robust　state-constrained　control　method　is　proposed　by　utilizing　a　robust　control　barrier　function　(RCBF),　the　quadratic　programming　(QP)　and　a　saturation　model　to　guarantee　the　visibility,　where　RCBF　can　accommodate　unknown　dynamics.　The　theoretical　analysis　demonstrates　the　asymptotic　stability　of　the　closed-loop　system.　Simulations　are　carried　out　to　further　validate　the　controller　performance.