Abstract: Cracking and leakage emerged in stainless steel coiler of heater at a regeneration gas site after 49 h running. Chemical compositions analysis, mechanical property test, penetrant test, macroscopic and microscopic feature analysis, intergranular corrosion test and energy spectrum analysis were performed to find the failure reasons. The results indicate that because some quite high concentration chloridion entered the heater coiler media, chloride stress corrosion cracking emerged in the coiler. Furthermore, protection measurements were proposed.