When ultrasonic testing is performed, the artifact appears in ultrasonic flaw detection image since longitudinal wave and transverse wave occur by mode conversion and receiving wave cannot be discriminated between these waves. The goal of this study is to discriminate between these waves in order to decrease this artifact. In this research, localizing method of AE source and three-axis sensors as receiver are introduced. The point where incident wave finally reflects before arriving at receiver is localized by utilizing localizing method of AE source. The propagation direction of received wave is estimated by using the localized point, and the vibration direction is measured by three-axis sensor. The angle between the propagation direction and the vibration direction is calculated. As a result, two angles are calculated in the case of assuming that received wave is longitudinal wave and the case that received wave is assumed to transverse wave. By investigating which of the angles value are closer to theoretical angle value, received wave is discriminated between longitudinal wave and transverse wave. The effectiveness of this discrimination method is verified by using ultrasonic propagation simulation.