Abstract: We take the tidal flat in Cao Zhuang, Xingcheng city, Liaoning Province as an example and build a two-dimensional hydrodynamic numerical model with MIKE21. Based on the verification of the tide level and tidal current (flow velocity and flow direction) in the stable deep sea, we verify the instantaneous waterline and tidal current (flow velocity and flow direction). This paper also includes the analysis of the tidal characteristics and the influence of strong wind on the results of the model. The results show that the tidal flat can be flooded during spring tide and neap tide, the average flooding time on the tidal flat is 5.8 hours. The flow field on the tidal flat is extremely complex, as the velocity on the tidal flat reaches a maximum of generally 30~40 cm/s during spring tide and the flow direction parallels to the shoreline. The strong breeze or moderate gale has a great effect on the flow field in the whole sea area, the calculated velocity value of No.1 and No.2 separately increase by 43.8% and 29.5%, comparing with the value under windless conditions.