Fatigue　failure　is　a　common　failure　mode　under　the　action　of　cyclic　loads　in　engineering　applications,　which　often　occurs　with　no　obvious　signal.　The　maximum　structural　stress　is　far　below　the　allowable　stress　when　the　structures　are　damaged.　Aiming　at　the　lightweight　structure,　fatigue　topology　optimization　design　is　investigated　to　avoid　the　occurrence　of　fatigue　failure　in　the　structural　conceptual　design　beforehand.　Firstly,　the　fatigue　life　is　expressed　by　topology　variables　and　the　fatigue　life　filter　function.　The　continuum　fatigue　optimization　model　is　established　with　the　independent　continuous　mapping　(ICM)　method.　Secondly,　fatigue　life　constraints　are　transformed　to　distortion　energy　constraints　explicitly　by　taking　advantage　of　the　distortion　energy　theory.　Thirdly,　the　optimization　formulation　is　solved　by　the　dual　sequence　quadratic　programming　(DSQP).　And　the　design　scheme　of　lightweight　structure　considering　the　fatigue　characteristics　is　obtained.　Finally,　numerical　examples　illustrate　the　practicality　and　effectiveness　of　the　fatigue　optimization　method.　This　method　further　expands　the　theoretical　application　of　the　ICM　method　and　provides　a　novel　approach　for　the　fatigue　optimization　problem.