Tidal gauge records are collected from three tidal stations in Lingdingyang Estuary. Fourier transform and inverse fourier transform are used to eliminate the components that periods are less than 4a from monthly mean time series. The secular trends of sea level are determined by means of linear regression of low passed time series. The empirical orthogonal function (EOF) is used to analyse the spatial and temperal characteristics of sea level change in Lingdingyang Estuary. The average rate of sea level change in Lingdingyang Estuary, which is estimated by the time series of the main mode, is 0.89 mm/a.