Fatigue　crack　growth　behaviors　of　Ti-48Al-2Mn-2Nb　alloy　produced　by　CSD　and　treated　by　HIP　were　investigated.　Fatigue　crack　growth　tests　were　conducted　under　load　control　at　room　temperature.　The　result　shows　that　the　fatigue　crack　growth　resistance　of　CSD　samples　is　better　than　that　of　HIP　samples.　It　indicates　that　the　lamellar　structure　for　CSD　has　a　better　resistance　to　crack　growth　than　a　duplex　structure　for　HIP.　Moreover,　SEM　observations　of　crack　growth　paths　are　shown　that　there　are　quite　different　models　from　CSD　and　HIP.　The　CSD　samples　show　the　main　crack　grows　tortuously　and　discontinuously　by　ligaments　bridging　many　microcracks　in　front　of　crack　tip,　while　the　smooth　or　almost　straight　crack　path　is　found　in　HIP　samples.