The failure mechanism of pipeline cracking area of ground flare burner was studied. Through the combination of low?power macro analysis, material analysis, microscopic metallographic analysis, scanning electron microscope (SEM) micro morphology and energy spectrum analysis (EDS) and experiment, the causes of pipeline failure and cracking were found out. The sensitive environment (medium), the influence of sensitive materials and stress conditions on pipeline cracking failure were further analyzed. The results show that at a certain temperature, an acidic corrosion environment of H₂S+CO₂+H₂O is formed in the pipeline, and the stainless steel material of the flare burner pipeline is seriously sensitized and has serious intergranular corrosion; Intergranular corrosion causes grain spalling on the surface of pipe wall, resulting in pitting pits, which become the crack source of stress corrosion cracks; The flare burner pipeline will produce a certain degree of stress concentration in the process of manufacturing, processing and device operation. Under the condition of corrosive medium, sensitive material and stress concentration, the flare burner pipeline will fail due to intergranular stress corrosion cracking.