Immobilized-metal affinity chromatography (IMAC) media was prepared. Iminodiacetic acid (IDA) was optimally coupled to the oxirane-activated gel at pH 13.0 and 60 ℃ in 0.1-0.15 g of IDA per ml of 2M Na2CO3 for 5-7 hours. The amount of coupled IDA was 600-800 micromoles per gram of dried gel by determining zinc (II) ion with atomic absorption spectroscopy. Adsorption and desorption of protein sample to IDA-coupled media was made and the result is compatible to ones reported previously. The efficiency of column chromatography was discussed on partially purifying β-galactosidase from E. coli as the protein sample by zinc (II) ion chelate affinity column.