The 1503 partial waste heat boiler of Daqing Petrochemical Co. 2nd chemical plant was built in early 2008.It was installed and used in 2008 July. Removing the stress treatment was completed after construction. And the pressure tests was made on the shell and tube sides in January 31, 2008 and December 1, 2008 .And at last detection was made and the test results were qualified. The 1503 partial oxidation waste heat boiler leaked in 2011 February, and the leakage of the furnace tube was analyzed by chemical composition, metallography, mechanical properties and some analysis. And the direct cause of leakage was confirmed due to the high temperature oxidation resulting in the decline of furnace tube material change and the strength properties decrease. Through the analysis of the composition of raw material, the final confirmation of raw material composition changed, and caused the tube internal fouling, the heat could not be took away, eventually led to overheating.