The geochemical features of the Late Permian tuff in Nanchuan District, Chongqing, southwestern China, were studied using the methods of inductively coupled plasma mass spectrometry(ICP MS), X ray fluorescence(XRF)，powder X ray diffraction(XRD), A scanning electron microscope equipped with an energy dispersive X ray spectrometer(SEM EDX). The results show that elements including Al, Ti, Li, Cu, V, Cr, Co, Ni, Nb, Ta, Zr, Hf, Ga, Sc, Th, U and REE are enriched, especially the concentrations of Ti, Nb, Ga and REE, which are higher than cut off grades of national standards of China, respectively. The potential comprehensive utilization of Ti, Nb, Ga and REE should be paid more attention. The concentrations of trace elements increase from the bottom of tuff to the top, and the rare earth elements (REE) in tuff have obviously differentiation, the upper portion of tuff enriched light rare earth elements(LREE) and medium rare earth elements(MREE), while the lower portion enriched heavy rare earth elements(HREE). The characteristics of elements and its assemblage in the tuff show that the materials of tuff may be originated from Emeishan basalt magma and of the mafic volcanic origin.