Mercury is a global pollutant that can be enriched in organisms and eventually endanger human health. In this paper, we studied the soil, plants, and animals in the sandy beach, winged alkali pong wetland, reed wetland, and rice field in Liaohe estuary in 2018 and 2019, measured the plant and animal carbon and stable nitrogen isotopes, and carried out the food chain construction by animal carbon and nitrogen stable isotopes, and studied and analyzed the accumulation of mercury from the producer to the consumer of the food chain. The results showed that the food chain construction at the sampling sites was as follows: S1: plants < flesh worms, ants < spiders; S4: plants < moths, leaf beetles, mosquitoes, ants < spiders; S6: plants < mosquitoes < spiders; S7: plants < flattened hooks, mosquitoes, ants < spiders; S9: plants < ants < spiders. The range of Hg in soil: S1: 0.087-0.175mg/kg; S2: 0.035-0.197mg/kg; S3: 0.089-0.249mg/kg; S4: 0.050-0.167mg/kg; S5: 0.024-0.150mg/kg; S6: 0.066-0.152mg/kg. S7: 0.035-0.165mg/kg; S8: 0.026-0.083mg/kg; S9: 0.035-0.191mg/kg. The range of Hg in plant samples: S1: 0.019-0.242mg/kg; S2: 0.019-0.161mg/kg; S3: 0.025-0.142mg/ kg; S4: 0.010-0.120mg/kg; S5: 0.015-0.269mg/kg; S6: 0.040-0.079mg/kg; S7: 0.014-0.300mg/kg; S8: 0.020-0.100mg/kg; S9: 0.022-0.208mg/kg. Constructing the food chain of In animal samples, the accumulation of Hg: S1: 0.061-0.355mg/kg; S3: 0.082-0.198mg/kg; S4: 0.051-0.230mg/kg; S6: 0.032-0.449mg/kg; S7: 0.078-0.195mg/kg; S9: 0.086-0.189mg/kg By comparing the data, the annual accumulation of heavy metals in soil and plant samples showed an increasing trend and combined with the trophic level relationship of the food chain, it was found that the accumulation trend of heavy metals increased step by step with the trophic level of consumers.