Based　on　the　topological　optimization　and　layered　decision-making　theory　of　multi-objective　optimization,　a　new　methodology　of　multi-objective　topological　optimization　design　(MOTOD)　was　proposed,　and　the　method　was　applied　in　the　optimization　design　of　structures　in　the　key　unit　of　ultra-precision　stages.　The　simulation　results　based　on　ANSYS　prove　that　MOTOD　significantly　improve　the　static　characteristics,　dynamic　characteristics　and　the　design　efficiency　of　multi-objective　structure　optimization　design,　satisfies　the　rigorous　requirements　in　performance　of　ultra-precision　structures,　and　provides　a　theoretical　guide　and　method　for　modern　structure　design　and　improvement.