Nodoushan clay deposit is located about 130km southwest of Yazd city in the Uromieh-Dokhtar volcano-plutonic belt. Based on the field, mineralogical and geochemical studies, the rocks of Nodoushan area are of volcanic type and are composed of dacite, andesite and olivine-basalt, the pyroclastic type (crystalline tuff), and the microgranodioritic intrusive rocks. According to Zr/TiO₂ versus SiO₂ and Nb/Y versus Zr/TiO₂ diagrams and field evidences, the mother rock of the deposit has dacite origin. The clay samples clearly indicate depletion of CaO, MgO, MnO and Na₂O with respect to the original rock. The lack of high-temperature minerals such as pyrophyllite, dickite and, the presence of quartz, K-feldspar, kaolinite, halloysite and illite minerals in Nodoushan deposit indicate the alteration zone to be of intermediate argillic type. In this deposit, the average of Cr and Nb is 11.26ppm, which is less than the amount given for supergene deposits. High concentration of Sr + Ba (1341.33ppm) is due to the effect of hydrothermally processes. By referring to mineralogy, geochemistry as well as a model given by researchers, hydrothermal origin can be confirmed for Nodoushan clay deposit with some extent of weathering effect.