This study is aimed at detecting diatom in lung, liver and kidney tissues using PCR - DHPLC technology after different periods of enzyme digestion to assess the effect of enzyme digestion on the detection of diatom species. Twenty Randomly selected experimental rabbits were drowned at the same place. Their liver, kidney, and lung tissues were removed for sampling. After the extraction of DNA from the samples, amplification was conducted with specific primers of the SSU gene of diatom. Then, an analysis was performed with agarose gel electrophoresis and DHPLC. Within 2 h-8 h, the amount of the diatom species found in the lung gradually increased over time and was statistically significant <. After 8 h, with enzyme digestion, the amount of the diatom species found in lung showed no significant increase (>). However, as for the liver and kidney, within 2h-6h, the amount of the diatom species gradually increased over time and was statistically significant <. After 6h, the fig. did not present significant growth (>). The amount of the diatom species found in the organs after different periods of digestion time had significant differences, which provides a reference for the detection of diatoms and also, has a good application prospect in the forensic identification of drowning.