The　existing　physical-layer　network　coding　(PNC)　only　considers　channel　codes　of　a　constant　coding　rate.　In　this　paper,　we　propose　a　rate-compatible　(RC)　channel　coding　scheme　for　PNC　in　two-way　relay　systems.　Our　contributions　are　as　follows.　First,　we　propose　a　two-edge-type-low-density-paritycheck-aided　PNC　(JTNC)　scheme　due　to　its　simple　implementation　and　excellent　performance.　Second,　we　design　an　RC　scheme,　i.e.,　choice　of　locations　and　symbols,　for　the　proposed　JTNC　in　the　relay.　The　simulation　results　show　that　the　proposed　RC-JTNC　has　good　error　correction　performance　and　achieves　large　gains　over　the　existing　puncturing　algorithms　aided　PNC　over　a　wide　range　of　rates.