Abstract: The high cycle fatigue behavior of TA16 alloy tube with the internal surface defect was evaluated. The defect of TA16 tube was examined by the method of ultrasonic flaw detection. Two kinds of TA16 tube were prepared: the traditional preparation technology has the crack-like and jagged defects, and the improved one has the shallow and wide defects. The high cycle fatigue was preformed under axial loading. The fatigue life of traditional tubes are between 1×10⁵ and 6×10⁵ cycles under the ultrasonic flaw detection from 25% to 90%. The life of improved ones is all above 10⁶ cycles. There is no fatigue crack source in the fracture surface. The crack propagation direction is from the inner surface of tube to the outside, which means that states of materials surface have some influence on the fatigue life.