A water wall burst accident occurred in the operation of a power boiler in an enterprise.Through the macro morphology analysis,material composition analysis,metallographic structure analysis and mechanical property detection of the cold wall tube samples of the burst tube,combined with the actual operation of the boiler,it is analyzed that the main reasons for the failure of the water wall tube burst are the original manufacturing quality defect of the steel tube and surface mechanical damage.According to the analysis results,the corresponding solutions and preventive measures are put forward to avoid the impact of the same type of failure on the safe operation of the boiler.