This　paper　talks　about　distributed　consensus　tracking　control　of　general　multi-agent　systems　with　unidentical　dynamic　uncertainties　over　directed　graphs.　Using　the　absolute　output　information　of　each　agent,　the　local　states　are　estimated　by　a　Luenberger　observer.　Then　a　distributed　feedback　controller　based　on　the　output　regulation　theory　is　constructed　for　consensus　tracking.　Further,　a　robust　stability　condition　is　derived　for　the　whole　multi-agent　systems　based　on　the　small　gain　theorem,　which　has　less　conservativeness　by　utilizing　the　frequency　characteristics　of　unstructured　uncertainties.　The　asymptotic　consensus　tracking　performance　is　ensured　by　the　developed　protocol　as　revealed　by　a　theorem.　Moreover,　the　exchanged　information　among　the　agents　is　only　outputs　of　neighbouring　agents,　which　greatly　reduces　communication　burden.　Finally,　a　case　study　validates　the　developed　method.