Abstract: A warehousing and logistics project along the coast of Tangshan Sea is located inside the Caofeidian Industrial Zone. The area completed the sea reclamation project in 2015, and the current site elevation is +4.5 m (the lowest theoretical tidal level in Caofeidian). There will be no new reclamation construction in the future. Due to the holistic nature of ocean morphology, complex motion patterns, and continuity of dynamic processes, the role of ocean engineering can alter the hydrodynamic state of the ocean under natural conditions, directly and indirectly affecting environmental factors such as topography, erosion and deposition, material transport, seawater quality, sediment quality, and habitat of benthic organisms. Therefore, the analysis of marine hydrodynamic environmental impact assessment is crucial. Based on the MIKE21 model, using two-dimensional tidal and diffusion basic equations, and referring to the hydrological data of the sea area measured over the years, the impact of land reclamation on the hydrodynamic environment of the storage and logistics project in the sea area is simulated. Through the verification of the calculation results of the tidal field, the changes in the tidal field in the sea area where the project is located were calculated. It was found that during the overall reclamation process of the block where the project is located, the flow velocity in the sand extraction area decreased, with a maximum reduction of about 0.16 m/s. However, there was an increase in the flow velocity on the east and west sides of the sand extraction area, with a maximum increase of about 0.14 m/s. The area where the flow velocity change exceeded 0.005 m/s can be controlled within a 2.5 km range of the sand extraction area. It will not have a significant impact on the overall hydrodynamic conditions of the region.