In　this　paper,　the　fatigue　crack　growth　rates　of　A7N01　aluminum　alloy　welded　joint　in　weld　zone　(WZ)　and　heat　affected　zone　(HAZ)　are　compared　under　the　stress　ratio　of　0.1.　At　the　same　time,　the　fatigue　crack　growth　rate　of　WZ　under　different　stress　ratios　is　studied.　The　results　show　that　the　difference　of　microstructure　leads　to　different　fatigue　crack　growth　rates　in　different　areas　of　welded　joints.　The　HAZ　shows　better　fatigue　crack　growth　resistance　and　slower　fatigue　crack　growth　rate.　However,　due　to　the　burning　loss　of　Zn　element　in　the　WZ,　the　precipitation　of　strengthening　phase　after　solidification　in　the　molten　pool　is　less,　and　the　fatigue　crack　propagation　resistance　is　weak.　After　60　days　of　natural　aging,　the　number　of　precipitated　phases　in　the　WZ　and　HAZ　increased,　and　the　fatigue　crack　propagation　resistance　is　improved　compared　with　that　in　the　welded　condition.　Compared　with　grain　boundary　strengthening,　precipitation　strengthening　is　more　important.　With　the　increase　of　stress　ratio,　the　fatigue　crack　closure　effect　in　WZ　gradually　weakens,　and　the　fatigue　crack　propagation　rate　increases.