To counter the severe environment of open sea construction integral bridge pier of Donghai bridge sea-crossing section, we adopt two U-shape steel sleeve boxes installed on the top of the integral bridge pier and then casting the bottom concrete and wet joints to form a dry construction environment under the principle of using as possible as we can the present craft and machinery within the lowest operation time. The construction technology of open sea bridge pier connecting with U-shape concrete sleeve box, stress analysis of different working conditions and construction technical measures are presented.