In this study, Probable Maximum Precipitation (PMP) and the corresponding return period were estimated. Then HEC-HMS model was calibrated to estimate the characteristics of the PMF in the Eskandari watershed, branch of Zayandehroud River. Firstly, using Hirschfield method and statistical distribution, maximum 24-hour rainfall amounts in different return periods were determined as well as PMP. Then, the next step by using two events with the best model efficiency cofficient, HEC-HMS model calibrated and then the model evaluated by two various other events and was obtained acceptable results.  Also, the estimation of PMF characteristics showed that precipitation 240.6 mm and 596374 year return period can generate flood peak 3079.5 m³/s and volume 178.1 Mm³.