Objective The sedimentary environment of the Pearl River Delta is complex with abundant Perinereis trace fossils. The characteristics， distribution， and assemblage of Perinereis and their relationships with sedimentary environment and sediment properties are significant for the study of trace fossils and the palaeoenvironment. Methods Based on sedimentary and ichnological methods， grain size analysis， salinity， turbidity， total organic carbon （TOC）， X-ray scans， and three-dimensional （3D） reconstruction were applied to the modern biogenic sedimentary structures in different microenvironments of the Pearl River Delta tidal flat， discussed the composition， assemblage， and distribution characteristics of Perinereis in a tidal flat of the Pearl River Delta， and analyzed the relationship between the biological assemblage and the sedimentary environments. Results （1） The Perinereis mainly lives in the tidal flat area of the tidal channel and the interdistributary bay in the Pearl River Delta. （2） The remains of the Perinereis mainly have grazing trails and dwelling trails. However， the grazing trails on the layer are difficult to observe， the dwelling trails in the layer mainly have simple Y-， I-， and U-shaped and complex network structures， and there are bulges at the joints. （3） The Perinereis is suitable for living in the tidal flat or channel of the interdistributary bay with low hydrodynamic conditions， low salinity， low turbidity， and rich total organic carbon content. Conclusions The spatial distribution of Perinereis neoichnology is imbalanced， and multiple environmental conditions jointly control the abundance of Perinereis neoichnology. The habitat of Perinereis is similar to the trace fossil Polykladichnus， which can belong to both the Mermia and Glossifunites ichnofacies； the trace fossil assemblage of this relic mainly appears in the channel and tidal flat area， and this study supplements the biological data for the modern neoichnology of Perinereis.