Abstract: Based on the latest research both on the mechanisms of river ice and on the theories of hydrodynamics, river mechanics, thermodynamics, river ice hydraulics, and mechanics of solids, this study developed a synthetic and dynamic mathematic model of river ice for the Baishan reach of the Songhua River (China). This model incorporates hydraulic, ice transport, thermal, and ice components, and the equations of the model are solved numerically using a finite difference method. The presented model was validated fully against 15-year series of comprehensive field observations including geomorphological, meteorological, hydrological, thermodynamic, and ice regime data, and the calculated results agreed well with the measured data. This study revealed that the Dawaizi reach, which is 4 km downstream of the Baishan dam, freezes first, and then the front of the ice cover progresses gradually upstream. Furthermore, the shape of the accumulated frazil ice on the underside of the ice cover is similar to that of the longitudinal profile of the riverbed in the Baishan reach. The presented results will be of value to studies of both river ice and ice damage control in northeastern China and in other cold regions.