FacetClumps extracts and analyses clumpy structure in molecular clouds. Written in Python and based on the Gaussian Facet model, FacetClumps extracts signal regions using morphology, and segments the signal regions into local regions with a gradient-based method. It then applies a connectivity-based minimum distance clustering method to cluster the local regions to the clump centers. FacetClumps automatically adjusts its parameters to local situations to improve adaptability, and is optimized to detect faint and overlapping clumps.