Single-crystalline PbS hexagonal nanoplates and microspheres assembled by nanocubes were synthesized via two-phase methods, where CS 2 acts as both sulfur source and one reaction medium, and N, N-dimethylformamide (DMF) or dimethyl sulfoxide (DMSO) acts as the other medium to dissolve lead source. The products were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray photoelectron energy spectra (XPS). After 4days' reaction at room temperature, the PbS nanoplates with an edge length of approximately 400nm and thicknesses of about 50nm were generated in DMF solution, while the nanocube-based PbS microspheres were obtained if using DMSO as solution. The possible formation mechanism of PbS nanoplates and microspheres has been elucidated.