A representative unit hydrograph responding to a small basin is used to calculate the flood discharge in the basin. The peak discharge and the time to peak of the unit hydrograph are dealt with its characteristic values. In this study it is shown and analyzed the fluctuations at peak discharges and times to peak of unit hydrographs by rainfall storms in a small national basin $8.5;km^2$ wide are no small. And on assumption that a major factor in the fluctuations of the unit hydrographs in a small basin be rainfall intensity of a rainstorm, both relations of peak discharge and time to peak with rainfall intensity are suggested as exponential functions respectively. In this result although it is a limit of the study in which its result is accompanied with not small dispersion in the peak values of unit hydrograph due to a defect in used data it is sure an averaging regression relation between peak discharge and time to peak with rainfall intensity as identified in this study has hydrological worth from the complementary viewpoint of the theory of unit hydrograph.