Abstract: The determination precision of temporary tidal gauge’s chart datum is influenced by tidalnature similarity,datum transfer distance and topographical environment characteristics.This paperhas studied the relationship between precision and influencing factors,and specific precision functionalmodels in south and north branches of Yangtze River Estuary have been given respectively,through alarge number of chart datum transfer tests with using tidal gauges’data in the Yangtze River estuary.The tests results indicate that the chart datum transfer precision in the south branch can be superior to8cm,when the difference of tidal type is less than 0.05and transfer distance is less than 80kilome-ters.While,the precision is 20cm in the north branch when the distance no less than 40km.The re-search achievement has an important significance to the determination precision of chart datum transferin the Yangtze River estuary.