Abstract: Spatial scale is a fundamental problem in GIScience. The representative fraction of map scale is the traditional typical meanings. Also we use spatial extent and spatial resolution/granularity to represent geographic information and phenomena on paper or in digital environment. But all these are built on our cognition and the interpretation of space and scale. This paper illustrates the significance of research on spatial scale, then discusses the connotations and meanings of spatial scale in cognition, granularity, extent, map scale