The　effects　of　aluminum　(Al)　on　the　microstructure,　hardness　and　wear　resistance　of　tungsten-copper　(W-Cu)　composites　were　investigated.　The　W-Cu　composites　were　fabricated　via　mechanical　alloying　and　spark　plasma　sintering.　It　is　found　that　the　Al　dissolved　in　the　metastable　W-Cu　alloy　can　act　as　an　＇intermediary＇　to　hinder　the　diffusion　and　phase　separation　process　of　Cu　out　of　W　during　sintering,　constructing　an　interpenetrating　nanostructure　where　Al　redistributes　in　W　and　Cu.　Correspondingly,　the　hardness　of　composites　increase　from　463.4　HV30　to　512.05　HV30　due　to　Al　dissolution　and　formation　of　the　nanostructure,　and　their　contributions　to　hardness　variation　of　the　original　W　and　Cu　regions　were　distinguished　by　nanoindentation.　In　addition,　the　wear　volume　was　also　reduced　to　less　than　a　third　of　that　of　original　W-Cu　composites　without　Al　addition　due　to　the　abundant　interfaces　and　mechanical　strengthening,　which　restricts　the　removal　of　W　and　propagation　of　cracks　during　the　wear　process.