The　purpose　of　this　study　is　to　evaluate　the　fatigue　life　of　heat　exchangers　used　for　Liquefied　Natural　Gas　(LNG)　and　to　ensure　its　structural　safety,　the　alternating　stress　of　brazing　structures　under　cryogenic　conditions　was　analyzed　with　a　Finite　Element　Model　(FEM).　Stress　concentrations　occurred　at　the　brazed　joint　with　a　maximum　alternating　stress　amplitude　of　153.45　MPa.　The　fatigue　life　of　brazed　structures　during　the　continuous　cool-down　and　heat-up　conditions　was　evaluated　based　on　the　ASME　standard　and　the　maximum　alternating　stress　amplitude.　Meanwhile,　structure　parameters　have　been　analyzed　for　their　influence　on　fatigue　life.　There　are　four　main　structure　factors　to　influence　the　life　cycle:　the　brazing　seam,　the　fin　thickness,　the　fin　distance,　and　the　fin　height.　The　life　cycle　will　decrease　with　increasing　the　fin　distance,　fin　height,　and　brazing　seam　thickness,　and　it　will　increase　with　increasing　the　fin　thickness.　In　addition,　in　order　to　predict　fatigue　life,　a　calculating　model　has　been　established　based　on　the　main　factors.　Finally,　the　fatigue　life　of　brazing　structures　was　also　tested　by　experiment,　and　the　microstructure　was　also　analyzed　for　the　fatigue　fracture　surface.　It　is　clear　that　brittle　fractures　along　the　brazing　seam　and　ductile　fractures　at　the　fin　roots　should　be　the　primary　failure　modes.　The　study　provides　a　base　for　LNG　aluminum　heat　exchanger　design,　manufacture,　and　safe　operation.