The conceptual rainfall-runoff model, HBV, was applied to Dongjiang basin and its 13 sub-basins for the purposes of examining the applicability of this well-known model in south China in order to explore the possibility of transferring the calibrated parameter values to ungauged basins. For testing the applicability of the model in gauged basins, an automatic optimization method was used for model calibration. For testing the transferability of the parameter values to ungauged basins, two parameter regionalization methods (proxy basin and global mean) to determine the model parameters for ungauged catchments in the study area were investigated. The results showed that: (1) the HBV model worked well in the Dongjiang basin with average R₂ higher than 0.82 for using calibrated values;(2) Transferring the parameter values with higher R₂ and ME during cross-basins tests into the hypothetic ungaged catchments did not result in better model simulations than those with lower corresponding values;(3) Neither area-weighted-mean nor Thiessen-interpolated-mean approach could markedly improve the precision of parameters estimation by arithmetic mean value. It was concluded that both regionalization methods could effectively estimate parameters for ungauged catchments in the Dongjiang basin, leading to little discrepancy in the two models.