Abstract: This study focuses on natural gas pipelines with high black powder content. Through a case analysis of an LNG pipeline, the composition of black powder impurities was identified using detection methods such as EDS and XRD, and their formation causes were thoroughly investigated. For long-distance natural gas pipelines containing significant black powder impurities, a three-stage pigging solution—“magnetic-jet-heavy-duty”—was proposed based on impurity characteristics to ensure effective cleaning. The research indicates that black powder primarily consists of iron oxides, iron oxyhydroxides, and sand, with its formation linked to improper pipeline construction and drying processes. The proposed pigging solution has been validated as effective in field applications, providing crucial technical insights for ensuring the safe and efficient operation of natural gas pipelines.