At present, the building exterior wall insulation material is one of the important items of interior decoration materials sampling inspection, which is not unrelated to its frequent fire accidents. For example, the CCTV building fire is derived from the use of non-flame retardant organic insulation materials. These materials will produce more smoke and toxic gases due to incomplete combustion and pyrolysis when they cause a fire, and most people inhale smoke and toxic gases to suffocate in a fire accident. Therefore, the fire risk caused by the building exterior wall insulation material is extremely high, which is easy to cause heavy casualties. The author combines the work experience to talk about the cause of the fire and the countermeasures to prevent it. Analysis of fire causes of 1. external wall insulation materials