Abstract: Variations of sea surface height in the Yellow Sea, East China Sea,South China Sea and Northwest Pacific have been obtained from TOPEX/Poseidon altimetry data corrected by CSR3.0,FES95.2 and the tide model established by authors respectively.It is shown by spectral analyses that sea level variations corrected by CSR3.0 and FES95.2 contain major components which are dominated by the annual and alias periods of principal tides constituent under T/P sampling.Nevertheless,sea level variations corrected by the tide model established by authors represent characteristic of non-tidal effects which means that tidal and non-tidal variations have been segregated correctly.And Fourier analysis shows that power spectral density is in proportion to deviation of CSR3.0 and FES95.2 compared with the tide model established by authors,which verifies the tidal aliasing is the mechanism of major components.In shallow area where the precision of the global tide models is lower,such as the seas adjacent to China,error of the tide models is higher than the real rule of variations of sea surface height in magnitude.Thus particular attention should be paid to the precision of the tide model in calculating variations of sea surface height.