Abstract: Based on Riemann approximation for the Godunov format, a two dimensional FVM model is developed for simulating the navigable hydraulic characteristics of the entrance area, and the interface flux is computed using the Roe format. By using the slope of water surface to reflect the effects of pressures instead of the source term, the stability calculation can be carried out in the complex terrain conditions. The rational division of dry and wet characteristic unit sloping bottom is made to ensure the water mass and momentum balance and numerical calculation accuracy of the calculated units. The navigable hydraulic characteristics of upper and lower entrance areas of the Tadi hydrojunction of the Qujiang River cascade and the conditions of electro-generation and flood release are calculated by this model. The simulation and analysis results show that the finite volume method of the Roe format can calculate the flow field stability under the complex terrain conditions and has a high precision of calculation, which can provide the data supports for the Qujiang cascade hydrojunction in drawing up reasonable rules and regulations in the future.