Abstract: The L(0,1) mode guided waves were investigated for detecting notch defects in small diameter and bending tubes of stainless steel. The tested tube has a diameter of 10 mm and a wall thickness of 2 mm. Firstly, finite element simulation models were established to analyze the mode conversion and reflection characteristics of L(0,1) mode at the elbow with different bending angles. It is observed that there is a non-monotonic relationship between the energy of reflected waves of different modes and the bending angles. Secondly, a magnetostrictive sensor is used to excite L(0, 1) mode with a central frequency of 90 kHz for detecting notch defects in the tested small diameter tubes under test. The effect of bending angle on the defect detection ability of guided wave is analyzed. The results show that the F (1, 1) mode generated at the elbow appears to disturb the performance of guided wave in detecting the defect behind the elbow. Using the proposed energy ratio β of featured wave packets as the characterization parameter, the guided wave can effectively detect the notch defects behind the elbow. Among the tested cases, the detection ability is the best when the bending angle is 90°.