Abstract: In order to address the issue of unstable numerical solution due to transition between supercritical and subcritical flows in local region in river-network modeling, the real flow status were firstly divided into four types including subcritical flow, supercritical flow, trans-critical flow, and shock, and then an adaptable model was introduced by increasing internal boundaries according to water balance and characteristics theory in the traditional Preissmann model. The final developed model preserves the advantages of the Preissmann model, which only need two points for each numerical template and can be easily integrated with mature river-network model. Numerical results for classic cases show that the introduced model is able to deal with gradual transition between subcritical flow and supercritical flow. A case study in Shiting river shows that the introduced model can converge to constant flow state using both single-river or river-network pattern, when frequent transition on supercritical and subcritical flow appears; this indicates the model can keep stable during complex flow modeling.