Provided is a method for evaluating spectrum utilization efficiency in a radio system sharing frequency. The method for evaluating spectrum utilization efficiency of a frequency sharing radio system in a radio environment having a first radio system using at least one specific frequency in an allocated frequency band and a second radio system sharing the frequency band allocated by the first radio system, includes calculating net coverage per unit area based on a design parameter on the first radio system and a design parameter on the second radio system; and evaluating spectrum utilization efficiency based on the calculated net coverage per unit area.