Abstract: In this paper, ROMS(regional oceanic modeling system) is used to simulate the temperature, salinity and current variations in Bohai sea, the Yellow Sea and the East China Sea using 40 year data with hourly tidal information. The output includes three-dimensional temperatures, salinities, velocities and sea level heights as well. These results were verified by comparing the simulated results with the observation and remote sensing data. It shows that the simulated water level is in good agreement with the observatories, including an accurate reproducing of the water level variations influenced by winds. The model accurately reproduces the temperature distribution in Bohai Sea, the Yellow Sea and the East China Sea. Also, the simulated thermohaline profiles in the deepwater area are consistent with the observed values. Compared with remote sensing data, the sea surface heights and sea surface currents simulated by the model are smaller, but the distribution patterns are similar. These model results can provide data support for studying the influence of climate change on water level and the diffusion process of warm tongue in the Yellow Sea.