A novel molybdenum disulfide-self-doped polyaniline(MoS2-SPAN) nanocomposite was successfully prepared by liquid exfoliation method. In the process of ultrasonication, the negatively charged SPAN diffused and intercalated in the MoS2 nanosheets to form a three dimensional-structured nanocomposite,due to the strong π-π* stacking interaction and electrostatic repulsion.The as-prepared MoS2-SPAN nanocomposite was characterized by scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR) and electrochemical method, which indicated that this nanocomposite had the advantages of a large effective area,a great deal of electroactive species and high stability.The electrochemical behavior of lead ions at MoS2-SPAN nanocomposite modified glassy carbon electrode(MoS2-SPAN/GCE) was investigated by differential pulse anodic stripping voltammetry(DPASV),and the electrochemical detection conditions for lead ions were also optimized. The results showed that the MoS2-SPAN nanocomposite possessed good conductivity and excellent adsorption performance for lead ions,and the MoS2-SPAN/GCE could realize the highly sensitive electrochemical detection of lead ions due to the large surface area and the good synergistic effect of MoS2-SPAN nanocomposite. Both, the MoS2-SPAN/GCE exhibited good linear relationships between peak currents and concentrations of Pb2+ in the ranges of 0.1-10μg/L and 10-100μg/L, and the limit of detection(S/N=3) was 2.87×10-8g/L.Besides,this electrochemical method based on MoS2-SPAN nanocomposite had an excellent repeatability and a good anti-interference ability, and it could be applied in the determination of lead in actual water sample.