Coated pipelines are widely used in industries such as chemical, petroleum, and gas. Cracks and localized corrosion caused by pipeline corrosion may pose significant safety hazards, making the detection of pipeline defects extremely important. However, the thicker coating on the pipeline makes it difficult for conventional non-destructive testing to detect defects in the pipeline. Pulse eddy current non-destructive testing technology, due to its strong excitation energy and excellent penetration ability, can detect defects in the pipeline without removing the coating. This study aims to analyze the effectiveness of defect detection under different signal characteristics. Firstly, a three-dimensional finite element model of a pipeline with a coating layer is established using simulation software. Secondly, differential voltage peak, differential voltage peak time, differential voltage zero crossing time, and differential signal fundamental frequency amplitude are selected as signal features to analyze the relationship between signal features and defects. Finally, a more suitable evaluation signal is selected. The simulation results show that the peak value of differential voltage and the amplitude of fundamental frequency increase with the increase of defect arc length and with the increase of defect depth. The peak time and zero crossing time are only related to depth, and increase with the depth of the outer surface and decrease with the depth of the inner surface. And by fitting signal features with defects, select signals suitable for defect resolution. This study helps to optimize the application of pulsed eddy current non-destructive testing technology in defect detection of coated pipelines, improving the accuracy and efficiency of detection.