A novel instrument that integrates reflection high energy electron diffraction (RHEED),electron energy loss spec-troscopy (EELS),and imaging is designed and simulated.Since it can correlate the structural,elemental,and spatial information of the same surface region via the simultaneously acquired patterns of RHEED,EELS,and energy-filtered electron microscopy,it is named correlative reflection electron microscopy (c-REM).Our simulation demonstrates that the spatial resolution of this c-REM is lower than 50 nm,which meets the requirements for in-situ monitoring the structural and chemical evolution of surface in advanced material.