[Background] In recent years,water cycle and water resource change have become more complicated due to the influence of climate change and human activities.Hydrological model is an approximate simulation of complex hydrological phenomena,which can realize the quantitative study of runoff.And parameter calibration is one of the most important steps in hydrological modeling.[Methods]In order to improve the calibration efficiency and simulation effect of the hydrological model,Hydrological Simulation Program in Fortran (HSPF) used extensively for assessing water quantity issues was selected in this paper.The PEST automatic calibration model with single objective function (squared error of daily flow) and multi-objective functions (squared error of daily flow,squared error of monthly flow,squared error of exceedance flow time) were applied in HSPF model,and the squared error of daily flow was improved by separating wet and dry seasons.These calibration methods were compared with Shanmei Reservoir watershed,southeast China.[Results] 1) Multi-objective calibration performed better with respect to goodness-of-fit measures (NSE,R~2,RMSE and PBIAS) than single objective calibration.In multi-objective calibration,the values of the NSE were above 0.79,the values of the R~2 were above 0.80,the values of the PBIAS were between-10% and 0%,and the values of the RMSE were < 30 m~3/s during the calibration and validation.2) In terms of the results of two multi-objective calibration methods,when the squared error of daily flows was improved by separating wet and dry seasons,the simulation results of daily and monthly runoff were significantly improved during the dry season.Taking daily runoff simulation for example,the values of the NSE increased from-0.04 and 0.43 to 0.25 and 0.54,the values of the R~2 increased from 0.37 and 0.59 to 0.47 and 0.64,the values of the PBIAS increased from-33.57% and-22.72% to-24.52% and-16.79%,and the values of the RMSE decreased from 9.54 m~3/s and 8.89 m~3/s to 8.06 m~3/s and 7.96 m~3/s during the calibration and validation,respectively.[Conclusions]The objective function has a great influence in the automatic calibration of parameters.Multi-objective calibration performed better with respect to the trend of runoff,total runoff,and flow duration curves than single objective calibration.When the squared error of daily flow is improved by separating wet and dry seasons,the problem of dry flow was neglected in traditional multi-objective calibration was solved and the simulation results of daily and monthly runoff were significantly improved during the dry season.