The　microstructure　and　mechanical　properties　of　a　novel　refractory　AlNbTiZr　high-entropy　alloy　(HEA)　with　a　low　density　of　similar　to　5.85　g　cm(-3)　were　investigated　after　arc　melting　and　homogenisation　at　1473　K　for　5　h.　The　as-cast　HEA　exhibits　a　single-phase　ordered　body-centred　cubic　(B2)　structure.　A　hexagonal　Zr5Al3-type　second　phase　is　introduced　into　the　HEA　through　homogenisation　treatment,　resulting　in　increase　of　the　yield　strength,　ultimate　compressive　strength　and　fracture　strain　by　70　MPa,　308　MPa　and　9.2%,　respectively.　These　results　indicate　that　the　introduction　of　the　hexagonal　Zr5Al3-type　second　phase　into　the　B2　matrix　can　simultaneously　improve　the　HEA　strength　and　ductility,　showing　a　strength-ductility　combination　superior　to　those　of　most　reported　refractory　HEAs.