A novel kind of ester has been synthesized as the ligand to prepare the PbS nanocrystals (NCs). When Pb(acac)2 (lead acetylacetonate) was used as the lead source, the (200) crystal plane of the ester capped PbS NCs became preponderant during the coarsening process along with the reduce of the contents of sulfide source. The ester ligand was stable and led to the formation of high quality PbS NCs. The broad XRD diffraction peaks are typical of nanosized particles. The HRTEM images showed well-defined, near monodispersed cubic particles.