Abstract: Based on case analysis and investigation, the authors consider that the early failure of field coating material for welded joint is a major category that influences the integrity of external coating of buried steel pipeline. This paper analyzes the failure cause of external coating of pipeline.It is pointed out that compli-cated coating process and difficul to site-coated construction result in the early failure of the coating material. According to the different performances and coating conditions of coating materials, the selection method of field coating materials for welded joint is presented.