: Soil is an important natural resources and its erosion has the social and economic vulnerability in addition to natural hazards. At the present study we evaluated the sedimentation rate of Toroq watershed by using PSIAC model in GIS environment. GIS analyses used in watershed management for attribution and classification of sedimentation rate as a superior technique. The aim was firstly zoning of sedimentation rate to identify sedimentation of the study area and secondly calculating the sedimentation rate (Q_s) and production (S) to classify them. According to our results the study area can be categorized into five erosive classes: very high, high, moderate, low and negligible. Also the results of zoning map in GIS showed that the high sedimentation zones in a meaningful distribution is observed in southern and northern parts of the watershed in which have the alluvial type of lithology and farming unit of land cover. The statistical analyses indicated that the sediment yield classes ranging from moderate to high with 60% of total surface area and sediment production of 84% of the total watershed. Analyzing the output map of PSIAC model showed that the calculated sedimentation rate in most parts correspond well with field observations.