Due to diverse applications of Lithium Nickel Manganese Cobalt (LiNixCoyMnz, NCM) composites in advanced electronics and material/alloy, the analysis of impurity composition is an important areas for evaluating its quality. In this paper, the sulfur determination in NCM composites by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) was proposed. The coexisting impurities effect of Si, Fe, Mn, Mg, Ca, Ni, Cr and main matrix was investigated. Using the optimized conditions, a good linear relationship of sulfur was exhibited in the range of 0-10 mg/L (r≥ 0. 9999), the standard addition recovery was 98.11-102.07 % and the RSD was 3.69 %, the levels of coexisting impurities lower than 5.0 % has no obvious interference on the determination of sulfur. This method could be served as a reliable determination of trace sulfur content in NCM composites.