Abstract: This paper introduces the theory and method for Earth rotation parameter solutions using GPS observations.After several tests and comparisons,more than 80 IGS reference stations distributed globally averagely were to provide observation data with a length of eight hours as a calculation epoch.The ERP time series at the middle point of an epoch with an interval of two hours was obtained by utilizing precise positioning software,GAMIT.The high-frequency time series of earth rotation parameter was initially de-noised by wavelet and then analyzed with fast Fourier spectrum analysis to get the diurnal and semi-diurnal ERP variations.Finally,high-frequency ERP variations with compared with tidal information to determine the excitation mechanism.