Robotic　assembly　lines　are　widely　applied　to　process　workflow,　increase　capacity,　and　easily　produce　a　wide　range　of　products　because　of　their　flexibility　and　multifunctionality.　Robotic　assembly　line　balancing　problem　(RALBP)　refers　to　allocating　the　tasks　and　robots　to　workstations　in　order　to　maximize　the　line　efficiency,　which　has　become　a　popular　research　direction　recently.　In　this　paper,　we　propose　a　mixed-integer　programming　model　to　optimize　the　carbon　footprint　of　the　RALBP.　Minimizing　carbon　footprint　can　reduce　global　greenhouse　effect　and　atmospheric　dust　pollution,　which　is　a　very　significant　environmental　topic　in　the　world.　We　also　investigate　a　realistic　production　process　design　in　our　model-cross-station　task.　In　this　design,　a　task　can　be　operated　by　the　station　to　which　it　is　assigned　as　well　as　the　adjacent　stations.　The　model　is　solved　by　a　commercial　solver　(Gurobi)　and　some　results　are　presented.　Copyright　(C)　2022　The　Authors.