Ion beam etching technologies for developing large aperture Diffractive Optical Elements (DOEs) were reviewed. To meet the requirements of large aperture DOEs in high-power laser systems, an integrated graphite mask for ion beams and a multi-position etching strategy were investigated for a self-established KZ-400 etching facility to improve the uniformity for ion beam etching and the uniformity of ±1% for ion beam current along the major axis of the ion source was achieved in a range of 1430 mm. On-line optical measurement methods and experimental setups for Multilayer Dielectric Gratings (MDGs) and transmission DOEs were presented to measure the 1D spatial distribution of diffraction intensity and the ion beam etching depth based on fringes of equal thickness,respectively, by which the quantitative control of ion beam etching for large size DOEs was completed. Based on above techniques, a series of large aperture DOEs, especially MDGs with diffraction efficiencies more than 95% at 1 064 nm, beam sampling gratings,color separation gratings and beam sampling gratings for synchrotron radiation were fabricated successfully.