Statistical characteristics of irregular waves which are described with power spectra have been investigated with computer simulation of one-dimensional wave profiles for twenty four shapes of wave spectra, each with five to ten runs. Simulated wave profiles were examined for the maxima of surface elevation, crest-to-trough wave heights, zero-up-cross wave heights, correlation between wave height and period, and the run length of wave heights.
　The numerical experiments show; i) the wave heights defined by the zero-up-cross method practically follow the Rayleigh distribution irrespoective of the spectral width parameter, ii) the correlation coefficient between wave heights and periods almost linearly increases with the increase of spectral width parameter, iii) the length of the run of zero-up-cross heights is most closely related to the peakedness of a power spectrum, iv) the representative height of wave system composed of wind waves and swells can be estimated with the use of energy concept. In addition, for laboratoty simulation of ocean waves with an automatically controlled wave paddle, the number of component waves for the input is recommended to be more than fifty.