The reformer furnace tubes have cracked after operating for in a service period in one plant, which lead to much economic losses. Therefore, it is necessary for us to carry on the over analysis of the reformer furnace tubes. The reformer furnace tubes were analyzed by using chemical composition analysis, macro-and micro-microstructure analysis, room temperature, high temperature mechanical properties analysis in the paper. The results show that the reason of failure for the furnace tube is the creep crack, and excess temperature is the direct reason for the creep crack. At the same time, the lack of the effect thickness in original design is the root cause of crack for the furnace tube.