The Erguna block is one of the most important Pb-Zn-Ag metallogenic provinces in East China. In this study, the laser ablation-inductively coupled plasma mass spectrometry ( LA-ICP-MS) and electronic probe have been used to determine the major and trace element concentrations of three generations sphalerites (sph1, sph2 and sph3) from the Erdaohezi Pb-Zn polymetallic deposit, a representative deposit in the Erguna block, in order to reveal the enrichment regulation and occurrence state of elements in sphalerites of the deposit, to explore physico-chemical conditions controlling the mineralization of the deposit, and to provide much more insights for discriminating genesis of the deposit. Our results show that the sphalerite is enriched in Fe, Mn, Cd, and In, but is depleted in Ga, Ni, Ge, Tl, and Se. From the earliest sphalerite generation (sph1) to the youngest sphalerite generation (sph3), the Fe and Mn contents of sphalerites are gradually decreased, whereas the Hg contents of sphalerites are gradually increased. Comparing to other two generations of sphalerite, the sph2 sphalerite contains relatively high concentrations of Cu, Pb, Bi, Sn, and Ag but relatively low contents of In. The time-resolved depth profiles and elemental correlation analyses of sphalerite reveal that elements including Mn, Hg, Cd, In, and Sn are mainly incorporated into the sphalerite lattice in the form of homomorphic substitution, Pb and Cu occurred mostly as mineral micro-inclusions in the sphalerite, but Fe and Ag occurred both as solid solution and mineral micro-inclusions in the sphalerite. The trace element contents and ratios of Zn/ Cd and Ga/ In of sphalerites indicate that sphalerites of the first two generations were formed under a condition of medium-high temperature and reduced environment, whereas the sphalerite of latest generation was formed under a condition of relatively low reduced environment at relatively low temperature. On the basis of field observations, previous studies, and characteristics of trace element of sphalerites using the in situ microanalysis, we have concluded that the Erdaohezi Pb-Zn polymetallic deposit belongs to an epithermal Pb-Zn-Ag polymetallic deposit related to late-stage subvolcanic rocks or concealed intrusions.