In the regional geological survey of urban geology and hydrogeology in coastal area of Jiangsu Province, full coring drilling is the main field work means. The sedimentary layers thickness are of 300～500m inequality, the deepest place is up to more than 800m. There is no precedent of coring in such thick sedimentary layer with such requirement in Jiangsu Province even in China. According to a drilling construction case, this paper summarizes the full coring drilling construction technology in very thick gravel layer of Jiangsu coastal area starting with drilling equipments selection, construction technologies determination and mud control technology, which could be referred in similar drilling projects in the future.