Abstract: The flow concentration process in basin can be considered as the movement in multiorder river net system. Based on this rational assumption, a new kind of IUH modelInverse Gaussian distribution model has been proposed in this paper. The model input can be used not only for surface net rainfall but also for total net rainfal. At the same time, for calibrating parameters efficiently, five kinds of simplified multiple objectives including the factor of time difference of peak between measured and simulated flow have been presented also, and the good results are achieved.