The prevention and control of heavy metal pollution in lake sediments has always been a hot issue in the environmental field. In this study, amino modified biochar was used as the covering material and Diffusive Gradients in Thin-films (DGT) was used to monitor the characteristics of in-situ release of Cu(Ⅱ) and Pb(Ⅱ) at the sediment-water interface with different pH and water flow disturbance conditions. The in-situ remediation effect of amino modified biochar on heavy metal pollution was also analyzed. The results show that the mobile heavy metal ions have a tendency to diffuse from the sediment to other media at 0 r/min or 100 r/min hydrodynamic conditions. The cover strength of 1.86 kg/m² for amino modified biochar can reduce the release flux of Cu (Ⅱ) and Pb (Ⅱ) over 89%, which effectively reduces the potential ecological risk of heavy metals in the water environment. A large amount of H⁺ or complex in the water will weaken the adsorption of heavy metal ions by amino biochar. When the overlying water is in neutral condition with pH=7, the in-situ remediation effect is the best. The content of Cu(Ⅱ) and Pb(Ⅱ) in the overlying water under the disturbance of 100 r/min water flow is 0.036-0.096 μg/mL higher than that at 0 r/min when the equilibrium is released. The high-intensity water flow disturbance easily caused the lifting and floating of the covering material, resulting in desorption of heavy metals escaping from the covering material.