In　this　technical　note,　we　present　an　output　feedback　control　for　the　cooperative　robust　output　regulation　problem　of　a　class　of　heterogeneous　minimum　phase　linear　uncertain　multi-agent　systems　with　the　arbitrary　large　plant　uncertainty　and　the　arbitrary　nonidentical　relative　degrees.　To　estimate　the　system　state,　we　propose　a　novel　distributed　observer　that　contains　two　distinct　parts,　where　the　first　part　is　of　the　distributed　form　to　estimate　the　regulated　error,　while　the　second　part　is　a　modified　version　of　the　standard　reduced-order　high-gain　observer　by　replacing　the　regulated　error　with　its　estimation　given　in　the　first　part.　Our　design　significantly　extends　some　current　literatures　in　that　it　strictly　removes　the　assumption　of　the　identical　relative　degree,　and　hence　applies　to　a　much　larger　class　of　linear　multi-agent　systems.