In　the　2016　International　Astronautical　Congress,　SpaceX＇s　Mars　immigration　plan　was　first　formally　proposed　alongside　a　fully-reusable　transportation　infrastructure.　In　the　12th　edition　of　the　China　Trajectory　Optimization　Competition　(CTOC-12)　held　in　2022,　a　Mars　transportation　trajectory　design　problem　using　reusable　transporters　from　a　parking　distant　retrograde　orbit　(DRO)　in　the　Earth–Moon　system　was　released.　It　is　expected　to　transport　as　many　immigrants　as　possible　using　a　maximum　of　50　transporters　within　a　total　of　20　years.　The　BIT-DFH-BJUT　team　reported　a　solution　that　can　deliver　9080　immigrants　to　Mars,　which　ranked　first　in　the　competition.　In　this　paper,　the　methods　and　results　from　the　winning　team　are　presented,　primarily　including　an　overall　analysis,　underlying　round-trip　trajectory　design,　and　top-level　scheduling.　Specifically,　a　round-trip　is　divided　into　four　phases,　leaving　the　DRO　to　man-boarding　at　the　perigee,　Earth–Mars　interplanetary　transfer,　Mars＇s　return　to　the　Earth,　and　return　to　the　DRO.　An　overall　optimization　framework　is　constructed　by　synthesizing　techniques　such　as　data　set　creation　and　patching,　differential　evolution,　nonlinear　programming,　greedy　algorithm,　and　mixed-integer　programming.　Finally,　we　outline　the　final　solution　of　our　team　and　compare　the　results　with　those　from　the　top　five　teams.　This　competition　demonstrates　that　a　large-scale　Mars　immigration　plan　is　possible　by　using　reusable　transporters　from　the　Earth–Moon　system.　©　2023　IAA