By using Y2O3/CeO2 powder, instead of part of Al2O3, acting as filler, Y2O3/CeO2-modified aluminide coatings were produced on Ni based using a conventional pack-cementation method at 600℃ for 10 h. For comparison, normal aluminide coating was also produced using pure Al2O3 acting as filler. Effect of Y2O3/CeO2 in the pack on the alumina phase transformation and cyclic oxidation resistance in air at 1000℃ was investigated. The results indicated that Y2O3 and CeO2 have a different effect for ?-? phase transformation: Y2O3 suppresses the growth of the ?-alumina but CeO2 promotes the q-a phase transformation. However, compared to the normal aluminide coatings, the addition of Y2O3/CeO2 significantly improved the cyclic oxidation resistance due to the formation of adherent alumina scale, especially the later. The effects of Y2O3 /CeO2 on alumina phase transformation and cyclic oxidation resistance are discussed in detail.