Objective To investigate the quantity and species distribution of diatoms in Chuanyang River of Pudong new area of Shanghai and provide references for the invesitigation of water body in forensic practice. Methods The water samples collected from 15 areas in Chuanyang River of Pudong new area in September 2012 were examined by microscope to identify the species of diatoms. Results Cyclotella and Pinnularia were found to be the dominant species within the 12 species of diatoms in Chuanyang River, which showed differences in species among the sections of Huangpu River, the center and the East China Sea. Conclusion The differences in subsectional distribution of diatom species in Chuanyang River may provide a new foundation for forensic identification in drowning cases especially in the deter-mination of falling location.