Abstract: Flood forecasting in ungauged basins is one of the most difficult tasks in hydrological research. In order to study the parameter transfer method of the HBV model in ungauged basins, The Tunxi catchment located in Anhui province was taken as an example. Based on the multi-objective functions, the HBV model can be simultaneously calibrated for multiple catchments. The parameters that can be used for different catchments were obtained in this case. The results indicate that parameter transfer based on the individual calibration shows larger uncertainty and unstable accuracy. Multi-basin simultaneous calibration can generally obtain parameters with strong stability, which can effectively improve the accuracy of parameter transfer and flood forecasting.