Tetragonal Cu3SnS4 nanostructures were synthesized in the solution precursors containing CuCl2·2H2O, SnCl2·2H2O and thiourea (NH2CSNH2) in ethylene glycol by conventional refluxing and microwave refluxing methods at an ambient condition. Cu(I)2Cu(II)Sn(IV)S4 of the as-synthesized products were detected by X-ray diffraction (XRD), selected area electron diffraction (SAED) and X-ray photoelectron spectroscopy (XPS). Scanning and transmission electron microscopy (SEM and TEM) revealed the gradual transformation of nanoparticles into curved nanoscales grown out of rods synthesized by conventional refluxing (CR) method, and into flower-like particles synthesized by microwave-assisted refluxing (MR) method. Prominent Raman peaks of CR and MR products were respectively detected at 316 and 318cm−1, including photoluminescence (PL) emission at 372nm and 367nm due to interband electron–hole recombination. Possible formation mechanism was also proposed according to the experimental results.