Abstract: Sea-level change and climate change are interrelated multiscale natural processes with profound spatial and temporal span connotation.Historical fact and event recognition of millennium to centennial scale sea level fluctuations and their relation to climate fluctuations are not only the foundation and theoretical issues of sea level change studies,but also very important for in-depth understanding of historical and future trends of coastal environment in both reality and conceptual issues.Based on land-sea level system,this paper integrates statistical analysis,simulation based on models and virtual environment test,and research on a variety of sea level change proxy data.The eastern China and global mean sea level series during the last 20ka are reconstructed based on 67 series selected from 130 global studies on regional sea level series and 12 Holocene series of China coast as well as 667 proxy data of historical sea level with different space-time scales.The fluctuations of different temporal scales are analyzed in details.The division of the millennial fluctuations in Holocene of eastern China and global average sea level is proposed as well as the division of centennial sea level fluctuations over the past 2ka.Then the correspondence between sea-level fluctuations and the global and China temperature fluctuations of the corresponding period are discussed.Based on the land-sea level system virtual simulation and experimental platform,the evolution of the sea-land relationship in the Yangtze River Delta is simulated,which suggests that the land-sea system evolution in Yangtze River Delta can be divided into early,middle and late stages.The early stage,spanning 10.0~7.0ka,is a period when sea level raised very quickly and the sea area expanded rapidly.In the middle stages,spanning 7.0~2.5ka,the sea level raised a little and sea area oscillated at a high level; In the late stage,spanning 2.5~0ka,the sea level decrease slightly and the sea area descended continuously.Then,from the perspective of fluctuations,the process of change of sea level and human-environment relationship in coastal zone is discussed.The impact of millennium to centennial sea level fluctuations in Holocene on the environmental evolution of coastal land and sea and on the human-environment relationships are analyzed emphatically.Finally,we proposed that the research on the Holocene land-sea interaction in the delta region and the coastal plain should move from using trend modes to fluctuation modes.