Up to now, there is no habitat suitability index model for Common Otter in Iran. This species is an index species for clean ecosystems and consequently, an important animal. Model prepared, considering dependent variables to show vital needs for this animal in the Shenrood River located in the Deylaman-Dorfak prohibited hunting area in Iran. HEP method was applied and important factors were selected used to reach habitat suitability index. It consisted of physical characteristics of the river such as mean of depth, mean of width, vegetation cover and distance to them. The model was built by mean of geometrical method using six variables. Model was applied on four sites, resulted 0/88, 0/79, 0/73 and 0/59 for respectively. First and second sites have got higher suitability score, which was similar to our observations in the field.