MIKE21 was used to establish a two-dimensional hydrodynamic mathematical model of Hongze Lake. By calibrating the model parameters, the calculated results of the model agreed well with the measured values, and then the hydrodynamic characteristics of Hongze Lake under different wind fields and throughput flow conditions were studied. We compared the flow field of Hongze Lake in 2013 under the wind speed of 0 m/s，5 m/s and 10 m/s, respectively. The results showed that the wind speed would change the intensity of the flow field but not the structure of the flow field. In addition, the effect of wind field would affect the outflow capacity of Hongze Lake, and the flow velocity of the lake area decreased with the increase of the wind speed. The throughput flow was the main factor affecting the flow field of Hongze Lake. The flow field of the inlet and outlet lakes changed significantly when the 2007 flood was used for simulation. The flow field structures in the Li River Basin and Chengzi Lake area of Hongze Lake were mainly determined by the wind field, whereas the flow field structures in the southern and eastern lakes were determined by both the wind field and the throughput flow, with the latter as the dominant factor. The results can provide a theoretical basis for the study of the material transport law in Hongze Lake.