The sedimentological and chronological study of Holocene reef sequence recovered in the drill core of Chenhang Island, Paracel Islands, South China Sea allows the reconstruction of reef growth patterns and sea level changes during Holocene. High-precision thermal ionization mass spectrometric 230Th ages for 22 in situ coral samples were obtained from the upper section of well Chenke-2(bottom:-878.21m; average recovery:60%), which provides extensive data due to complete core recovery and a success of basement drilling. And sedimentary facies analysis was made based on grain size data and organic components of 21 debris samples. Holocene growth began around 7900y BP at 16.7m, which is consistent with the time of reef initiation among most of the Indo-Western Pacific, Central Pacific and Caribbean reefs. The whole Holocene part is a reef flat deposit and consists of three sections, which are composed of principally coral and coralline algae clasts accounting for 68.95% and 17.88% respectively. Vertical accretion rates averaged 3.48 m kyr-1 , and to be more specific, the reef grew upward at about 6.44 m kyr-1 from 7900 to 6100 y BP, and then there is a broad inflection during 6100 to 4000 y BP with the vertical accretion rate slowing down to 0.87 m kyr-1. And different from other studies in this region, the lateral expansion of the reef took the position completely around 4000y BP, which is to some extent earlier than reefs in Spratly Islands. The reconstructed sea level curve, representing detailed Holocene curve based on U-Th dated corals within Paracel Islands, is characterized by a rapid rise between 7900 and 6500y BP, followed by a slight inflection around 6500y BP, and then stabilization to its present level around 5500y BP. Finally sea level peaked at approximately 1.5m above present mean sea level around 4000y BP.