Comparison of creep properties and failure analysis for HK and HP using as reformer tube in petrochemical plants were studied. Creep tests were performed at 800oC, 900oC and 1000oC for 100 to 1000hr range.To analysis of test specimens after creep testing, hardness test and microstructure analysis were carried out. Creep rupture strength of HP showed higher than that of HK . Cavities were nucleated between eutectic carbide and matrix and grown to pore type sourced of crack propagation. Eutectic carbides and secondary carbides were mainly composed with cr carbide containing small amount of Mo. After creep testing, hardness decreased regardless of HK or HP, and which seems to be caused by coarsening of both eutectic carbides and secondary carbides.