A novel method was developed to embed PbS nanocrystal with rod-shape morphology and small size in UV cured polyurushiol matrix through coordination. In the course of UV irradiation, the crosslinking of the long unsaturated side chain on the phenyl ring of urushiol-lead monomer took place to form polyurushiol-lead polymer. The hydroxyl groups on the phenyl ring of urushiol acted as the coordination sites for lead ion aggregations, and the nanosized PbS particles were successfully assembled to form rod-shape morphology in situ at these sites with the release of S 2− ions from thioacetamide. The phase and morphology of nanocomposites were characterized by XRD and TEM. The results showed that PbS nanocrystal was homogeneously dispersed in polyurushiol matrix with a typical diameter estimated to be ca. 3 nm, and with an average length about 8 nm. A possible formation mechanism of PbS nanocrystal in the polyurushiol matrix was also suggested based on the experimental results.