Abstract: With the development and construction of the comprehensive experimentation area in Pingtan,major breakthroughs and progresses have been made in the construction of various infrastructures. In order to alleviate the contradiction between land tension in the island and the further development of the comprehensive experimentation area,a series of large-scale reclamation projects have been carried out. Meanwhile,the Haitan Strait is also an important sea sand mineral base. Hence,there are a lot of sea sand mining activities around the Haitan Strait,which would reduce the beach surface,make the coast vulnerable in wave attacks,make the reefs bare,and affect the coastal tourism and the strengthen of the coast. Based on the analysis of water depth data in the Haitan Straight in 1999,2007,2010,2013 and 2015,the topographic change and profile change in this area and its influence factors were studied using triangular mesh technology. The results indicated that except the area from Heping Village to Zhuyukou,the whole research area was in the state of slight siltation from 1999 to 2015 and the silt thickness ranged from 0.5 m to 2.0 m. Due to the influences of reclamation and navigational channel dredging,there were strong changes in the erosion and deposition of the seabed terrain in partial areas. Favorable sedimentary environment and abundant sediment sources lead to a lot of high-quality sea sand resources in Haitan Strait. According to statistics analysis,the reclamation area of Xingfuyang,and Jinjing Bay and Jinjing Operating Area reached 14.61 square kilometers and 10.29 square kilometers,respectively. As a result of the exploitation of a large amount of sea sand,there was a severe scour in the area from Heping Village to Zhuyukou with an average scour thickness of 1.77 m and annual average scour rate of 0.11 m/a. Because of the scour quantity in the western Xingfuyang scour area was far greater than the silt quantity in the rest part of the research area,the whole research area was shown as a net scour state with an average scour thickness of 0.29 m and annual average scour rate of 0.04 m/a.