XRD, FTIR, NH3-TPD, pore structure and n-heptane cracking reaction were used to characterize the properties of ASDY and AEDY samples prepared by treating SDY and EDY with KOH solution at 373K respectively. It is confirmed that realumination of SDY was caused by reinsertion of the extraframework aluminum into the zeolitic framework and some Si atoms in SDY framework can be removed in 1.0mol.dm^-^3 KOH solution. EDY sample also can be realuminated by treatment with alkaline without additional aluminum species. We suggested that the surface and framework around secondary pores were dissolved by KOH solution, then reinsertion of aluminum into the framework vacancies of EDY occurs.

Key words: INFRARED SPECTROPHOTOMETRY, ZEOLITE, X-RAY DIFFRACTION ANALYSIS, TEMPERATURE PROGRAMMING DESORPTION, HEPTANE, CRACKING REACTION, FOURIER TRANSFORM, CATALYTIC ACTIVITY