The aim of this study is to investigate the boiler tube failure mechanism using finite element analysis and experimental Analysis. The numerical software used is ANSYS steady-state thermal and static structural analysis. The independent variable for the analysis is temperature from flue gas and wall thickness of boiler tube. The scope of the study is to determine the temperature distribution, von mises stress, deformation and safety factor by implemented design of experiment. The material of boiler tube sketch in two dimensional for simulation is SA210 Grade C. this is standard requirements for the boiler made of seamless medium-carbon steel with superheater tubes according to ASTM. From the result and discussion, the potential of failure mechanism will determine upon independent variables. In addition, hoop stress or circumference stress will help to support the statement of failure of boiler tube.