Abstract: This paper proposed a method for detecting leakage in domestic waste landfill based on traveling wave ELM method. The new coaxial cables were laid in parallel and evenly spaced in the soil layer under the HDPE film. Due to the corrosion effect of the landfill leachate, the physical properties of the insulating protective layer and the dielectric layer of the coaxial cable were changed, thereby resulting in a solid conductor layer and the metal shield was short-circuited at the leaking plot and then generated a transient traveling wave. The main components of the traveling wave spectrum were extracted from the transient current traveling wave for preliminary leakage positioning. The regression characteristics of the ELM were used to reduce the detection error caused by the variation of distributed inductance and distributed capacitance in the cable in the leakage zone. The experimental results showed that the signal energy transmission of coaxial cable was concentrated, the positioning accuracy of traveling wave frequency method was not affected by the leakage distance, and the maximum error of leakage positioning after ELM optimization was 0.535%.