A hexagonal Cu2SnS3 with uniform and well-dispersed nanoparticle morphology has been synthesized, representing an example of hexagonal system in the Cu–Sn–E (S, Se) ternary chalcogenides. Both theoretical calculation and experimental results give the unique metallic character of Cu2SnS3, which is significantly different from the traditional opinion that I-IV-VI ternary chalcogenides were regarded previously as small or middle band-gap semiconductors. Also, M(I)2SnS3 (M = Ag, Au, Rb, and Cs) serial compounds are another potential family of conducting sulfides. The conducting Cu2SnS3 product with the interlayer space and tunnels in the crystal structures could be fascinatingly introduced to the lithium battery application.