In recent years, the development had a rapid growth and brought major adverse effects on to the environment. In Iran, Cement plant is one of the common industries, which dramatically developed in recent years. According to the National Environmental laws, the Cement plants required to have environment impact assessment as they affect the environment significantly. Sabzevar Cement Plant has been established near Parvand Protected Area. Therefore, the significant impacts are expected. Usually, quantifying such impacts is complicated and ambiguous. The aim of environmental impact assessment is to quantify the significance of environmental impacts stemmed from the Sabzevar Cement Plants in operation phase. The impacts significance is hardly measurable; therefore, it should be broken down to lower level parameters, which are measurable. FUZZY sets and FUZZY logic are appropriate tools to reach the aim. In this study, the affected “Environment” was broken down into lower levels as environmental subsets as a hierarchical model. To identify the environmental impacts, the Léopold matrix was applied. Then, linguistic variables of each impact were introduced to the fuzzy system; and the value of each criterion such as magnitude, direction, probability, time and extent was calculated. In order to determine the significance of each impact, calculated values ??for each criterion introduced as input values to the next phase of fuzzy system. When the FUZZY system run, significance values were calculated for each impact in the level of environmental subsets. According to calculated significance values at the level of environmental subsets, the significance at the level of environment sets was calculated. Therefore, our results showed that Sabzevar Cement Plant has major impacts on the natural environment where the calculated significance using FUZZY logic are a - 50, -54/3, -49/9 and +50 for Physical, Biological, Aesthetic, and Socio-Economic impacts, respectively. Therefore, the most negative impact stemmed from the Sabzevar Cement Plants is on the biological environment, which is because the vicinity of the Cement plant to protected area and establishing the plant in a sensitive environment. Key word: Environmental Impact Significance, fuzzy logic, Sabzevar Cement Plant
