The samples coral reefs collected from Hai Nan Island and Xi Sha Island and Lei Zhou Peninsula in and at the margin of the South China Sea are dated at 6000 -7000 years old by 230Th/234U method.The levels of Sr in the coral reef samples are varied between 7.3 and 8.5‰, and are similar to that of coral reefs in the Florida and the Bahamas and the Persian Gulf indicating normal range 7.74 to 8.5‰. The relatively low Sr content for example Sh-06, can indicate the processes of recrystallization into calcite. It may be that Sr concentration and its variation in coral reefs are an additional criterion for cheking closed system.The results obtained by using 230Th/234U are compared with 14C ages for the same specimen. 230Th/234U ages for these samples appear to be 1500-2000 years older than 14C age estimates. It is tempting to conclude that the difference reflects in some measure the 14C yaers-sideral time discrepancy, because the 14C variations in the atmosphere are known for the last 8000 years.The apparent rates of vertical diaplacement estimated on the basis of the radio-metric ages including 230Th/234U and 14C slow the local variations within the South China. Sea for the last 7000 years and the average uplift rate was about 1-2 mm/yr.Holocene transgression probably began at the Late Pleistocene and continued rapi dly until about 7000 years ago, after which the rise was more gradual. If the ages determined by 230Th/234U method are correct, then it will suggest that, according to Fair-bridge’s sea-level curve, Paleosea levels associated with the early Holocene reefs from the South China Sea stood higher than at present no later than 6000-7000 years ago.