In this paper, simulation results of an electromagnetic field and mode distributions in a cylindrical reverberation chamber were presented. Reverberation chamber is an alternative test facility for a semi anechoic chamber, which is widely used for the analysis and measurement of electromagnetic interference and immunity tests. The method of computing the number of modes in a cylindrical reverberation chamber was presented and the number of modes in a cylindrical reverberation chamber with the same volume was compared with the different ratio of radius to height. The FDTD method was used to produce field characteristics inside of rectangular, right-angled isosceles triangular, and cylinder type reverberation chambers with the same test volume.