After the “8.8” earthquake (June 2020), Arrow Bamboo Lake and Rhino Lake, with different input degrees of earthquake damage sources, were selected to analyze the lake sedimentation rates by isotope dating method. Moreover, vertical distribution characteristics of grain size composition, total carbon (TC), total nitrogen (TN), total phosphorus (TP), and carbonate content were analyzed. By analyzing the vertical variation characteristics of sediment environmental indicators and their relationship with natural disasters and human activities, the long-term and short-term factors affecting lake sedimentation were explored. The results showed that the sedimentation rates of the Arrow Bamboo Lake and Rhino Lake from 1900 to 2020 were about 0.32 and 0.44 cm/a, respectively. The vertical distribution characteristics of the environmental indicators on the surface (0–10 cm) were as follows: the specific activity of ²¹⁰Pb_ex significantly increased, the sediment particle size was relatively large, TC, TN and calcium carbonate were enriched, and the vertical variation was violent. Meanwhile, the disturbance depth of surface sediment in the Arrow Bamboo Lake, which was obviously affected by seismic damage sources, was greater. These revealed that a large number of loose material sources of land disasters caused by the “8.8” earthquake entered the lake, rapidly intensifying the lake sediment deposition in the short time. The deep vertical distribution features recorded the long-term slow impact of human activities such as deforestation, unreasonable discharge and environmental protection on lake sediment.