In order to realize ductile machining of optical glasses using mono-layer nickel electroplated coarse-grained diamond grinding wheel, a novel conditioning technique features using a copper bonded diamond grinding wheels of 15m grain size dressed by ELID (electrolytic inprocess dressing) to condition the 46m grain sized diamond wheel has been developed. During the conditioning process, a force transducer was used to monitor the conditioning force, a coaxial optical distance measurement system was used to in-situ monitor the modified wheel surface status. White-light interferometry (WLI), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to characterize the conditioned wheel surface status as well as the ground optical glass surface topography correspondingly. The experimental result indicates that a minimized wheel radial run-out error of less than 2μm as well as the top-flattened diamond grains of constant wheel peripheral envelop profile were generated on a 5-axis ultra-precision machine tool. The grinding experiment proved that the well conditioned 46μm coarse-grained diamond wheel can be used in realizing the ductile grinding of optical glass BK7, which indicates that the newly developed conditioning technique is feasible and applicable to introduce the coarse-grained diamond wheels into precision machining of brittle and hard-to-machine materials.