The purpose of this descriptive-correlation study was to investigate effective factors on rural people’s non-participation of Mahabad’s dam catchment in Watershed Management Projects. The research instrument was structural questionnaire with close-ended questions, which its validity confirmed by panel of academic staff and reliability of questionnaire was confirmed. The target population of this study consisted of all householders who lived in Mahabad’s dam catchment (N=2458) out of them, according to Cochran's formula 175 people were selected by using cluster sampling in a simple randomization method (n=175). The descriptive results showed lack of financial ability for participating in watershed management, lack of awareness about watershed management efficiency, the long- term rate of return on the investment attracted in watershed management were the main variables related to rural people’s non participation in watershed management. By applying Factor Analysis Explanatory Technique, effective factors on rural people’s non-participation in watershed management were reduced to five factors namely weakness of agricultural extension services, getting watershed management out of governmental control, no achieving success to implement another rural projects by government, and no considering local individuals or organization by government. These five factors expressed 84% of the total variance of the non-participation people on Mahabad’s dam catchment in watershed management projects. Therefore points to these factors could solve the barriers of non-participation people on Mahabad’s dam catchment in watershed management projects.