Aiming　at　the　sway　velocity　and　uncertainties　such　as　wind,　wave,　and　current,　a　state　feedback　H　infinity　control　method　is　proposed　to　improve　the　dynamic　and　steady-state　performance　with　line　of　sight　(LOS)　law　for　trajectory　tracking　of　an　unmanned　surface　vehicle　(USV).　First,　a　novel　LOS　is　proposed　for　trajectory　tracking　with　the　position　error　to　obtain　the　references　of　surge　velocity　and　heading　angle.　Second,　the　LPV　model　is　established　with　varying　parameters　of　the　sway　velocity　for　the　USV.　Third,　the　closed-loop　system　for　the　LPV　model　is　established　by　the　state　feedback　H　infinity　control　method　to　design　the　controller.　Since　the　coupling　term　of　system　coefficients　in　the　Lyapunov　stability　condition　is　difficult　to　solve　directly,　a　novel　variable　is　introduced　to　decouple　the　stability　condition,　which　can　be　solved　with　MATLAB　LMI　tools　for　the　controller　parameters.　Finally,　the　simulation　result　shows　that　the　proposed　method　has　super　performance　on　the　dynamic　and　steady-state　indices.