The hemispherically capped rod-plane gap has been extensively used for studies on corona and breakdown characteristics of gaseous dielectrics. The field distribution of a hemispherically capped rod-plane gap can be computed using various methods. In this study, utilization factor of the rod-plane electrode system for different electrode gap spacing was computed by Charge Simulation Method (CSM). Then the computed results were compared with values computed by formulas of other researchers. There is a good agreement between the values computed with CSM and other methods reported in literature. As a results, utilization factor computed by this method can be used to compute the corona inception voltages and breakdown voltages accurately without having recourse to approximations.