In this paper, the mechanical behavior of local sharp-notched circular tubes under cyclic bending was experimentally and theoretically investigated. The material of the tubes was SUS304 stainless steel. The local sharpnotched depths included: 0.2, 0.4, 0.6, 0.8 and 1.0 mm, and the local sharpnotched directions included: 0, 15, 30, 45, 60, 75 and 90. According to the experimental result, the moment-curvature curve exhibits cyclic hardening and becomes stable after a few cycles. The notch depth and direction have almost no influence on the moment-curvature relationship. The ovalizationcurvature curve shows an increasing and ratcheting manner with the number of cycles. The notch depth increases, the unsymmetrical phenomenon of the ovalization-curvature relationship becomes more obvious and the ovalization increases faster. In addition, the ovalization- curvature relationship becomes more symmetrical and the ovalization increases slower when the notch direction increases. Finally, finite element software ANSYS was used to simulate the moment-curvature and ovalization-curvature relationships. Although the experimental and theoretical results had some differences, but both trends were similar.