Structure damage will affect the propagation of ultrasonic guided waves.Hence, non-destructive testing technology based on ultrasonic guided waves can realize structural health monitoring (SHM). A pipe with 174mm inner-diameter and 194mm outer-diameter, made of 20# carbon steel is used to investigate the damage localization in this study. Based on dispersion equations, numerical method is applied to obtain longitudinal and circumferential guided waves in the pipe structure. Central frequency of the incident signal is selected 80 kHz by simultaneously considering the dispersion curves and wave structure. Finite element method (FEM) is used to verify characteristics of guided wave propagation. According to the FEM analyses, characteristics and wave structures of longitudinal modes are close to those of circumferential waves, moreover, both of them are similar to those of Lamb waves in plate structure. Elliptical damage localization method is therefore proposed with one excitation and multiple captures for damage localization in the structure. Notch and hole are introduced to the pipe to verify effectiveness of the proposed method, and then analyzed influencing factors of damage localization deviation.