Abstract: Aiming at the damage of materials with different properties in the inner and outer layers of aluminum cable steel reinforced (ACSR), the detection technology and device for effectively identifying and locating the broken wires inside and outside the conductor are developed. The principle of this method is to excite and receive ultrasonic guided waves in steel core and aluminum strand by magnetostrictive force and Lorentz force. Firstly, The propagation characteristics of ultrasonic guided wave in ACSR are analyzed theoretically.; Secondly, the ultrasonic guided wave signals of aluminum strand and steel core under different degrees of broken wire damage are obtained through experiments; Finally, the signal is analyzed by wavelet transform, and the broken wire damage identification and location of different structural layers are realized. The research shows that the ultrasonic guided wave detection technology excited by magnetostrictive force and Lorentz force can effectively detect the internal and external mechanical damage of ACSR.