Microcolumns are widely used for parallel electron-beam lithography because of their compactness and the ability to achieve high spatial resolution. A design of an electrostatic microcolumn for our recent nanoscale photoemission sources is presented. We proposed a compact column structure (as short as several microns in length) for the ease of microcolumn fabrication and lithography operation. We numerically studied the influence of several design parameters on the optical performance such as microcolumn diameter, electrode thickness, beam current, working voltages, and working distance. We also examined the effect of fringing field between adjacent microcolumns during parallel lithography operations.