In this study, dredged sediment from Baiyang Lake was used as raw material to prepare DSB at a pyrolysis temperature of 600 degrees C and in an anoxic pyrolysis atmosphere. The adsorption and removal performance of tetracycline in water of DSB were investigated using fulvic acid (FA) as the activator. The biochar materials were first characterized (SEM, BET, XRD, FTIR, and XPS), and the elemental composition and surface functional groups of F-DSB were investigated. The maximum adsorption capacity of F-DSB, according to the Langmuir model, was 72.3 mg/g. Results demonstrated that F-DSB exhibited good adsorption performance. In conclusion, FA is a potential green modifier that can be used to improve the adsorption properties of DSB. This research will be useful in improving our understanding of the possible adsorption mechanism and process optimization of modified DSB. This work offers a novel approach to the resource utilization of dredged sediment.