Highly regular patterns with amazingly well-defined uniform truncated octahedrons of PbS nanocrystals as building blocks were prepared via a simple one-pot solution method. Each truncated octahedron has a composition of six {100} squares and eight {111} hexagons, and the overall structure shares 24 identical edges in a mecon way. Hexapod PbS, six-arm star-shaped dendrites, octahedron and truncated cubes were also fabricated. Structural and optical properties as well as morphological evolutions were studied by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and a confocal Raman spectroscopy. A mechanism for the formation of the PbS nanocrystals as well as their inner structure was tentatively proposed based on the characterization results.