Hui works on estuarine and coastal dynamics, with observational and modelling methods. In 2001-2008, he worked as a PhD student first and an assistant researcher later to develop the saltwater intrusion modeling system in the Changjiang River Estuary. During this period, he reconstructed the framework and I/O rules of the ocean model ECOM-si and introduced the wet/dry and adaptive time-stepping methods. This model has been widely used in the applied and scientific researches till now. Since 2009, he built a Yellow and East China Seas modeling system, created the advection algorithm HSIMT, and developed the de-tiding survey method PAMS. With these new tools and methods, he studied systematically the behavior and dynamics of river plume and coastal currents under a tidal environment.