ThispaperfocusesonstudyinglongdistancetransferenceofheightdatumacrossseasbycombiningellipsoidalheightderivedfromGPSwithgravimetricgeoidheight.TheYellowSeaHeightDatumistransferredtoYangshanIslandwhichis30kmawayfromLuchaoganginShanghai.Thestationsheightsderivedinthiswayarecomparedwiththosedeterminedfromtwoindependentsetsofthetidalobservationstakenintwoyears,andthedifferencevaluesare1.0cmand6.0cm,respectively.Moreover,thederivedheightdifferencesbetweentwosectionsontheislandarealsocomparedwiththevaluesderivedfrompreciselevelingwithrespecttothesamesection.Theresultshowsthattheinconsistenciesareonly0.2cmand0.7cm,respectively.