This paper describes the demonstration of an automated procedure for calibrating of AFFDEF model parameters. For this purpose, SCE algorithm which linked to the code of AFFDEF model, was used to calibrate spatial variation of model parameters. nine parameters were used to calibrate‌ simulated discharge of Kameh catchment which is located in the northern part of Torbat e Heidarieh township in Iran country. Two historical floods‌ were used for calibration and one for validation. The objective function, which is minimized by genetic algorithm, was computed as the sum of the squared differences between simulated and observed discharge in the model subroutine, coded in Fortran software. The results showed that the SCE technique linked to AFFDEF as a simulation-optimization model, can provide satisfactory result‌s in calibration period. But unsatisfactory in validation stage which can be‌ interpreted that parameter values according to the catchment hydrological conditions‌ that obtained from calibration flood events may not be representative for another flood event (validation flood event) which made more the‌ necessity of having more flood events and adjusting them based on other flood events hydrological conditions.