Abstract: To solve the problem of the tube explosion of the secondary platen superheater in a 350 MW sub-critical coal-fired power plant, analyses were conducted on the tube explosion reason with the macro-morphology observation of the burst, the hardness measurement, the logic analysis of the attemperating water for superheater, etc. Results show that the tube explosion is caused by the short-term overtemperature of the superheater tube, which is resulted from the water plug of the superheater. The tube explosion possibility of the platen superheater can be reduced through optimizing the logic the of the attemperating water for superheater and formulating multi-level preventive measures. This may ensure the safety and stability of the unit operation.