The flood resource utilization (FRU) is an important strategy for optimal operation of the Three Gorges Reservoir (TGR), and its influence on reservoir sedimentation is widely concerned. Relevant studies on flood events can deepen our scientific understanding on reservoir sedimentation. Besides, they may provide some technical supports to the TGR operation. This study investigated the flood runoff and sediment transport processes and the influences of the FRU on sediment deposition and delivery by statistical analysis of hydrological data from 2013 to 2021 and numerical simulation of flow-sediment movement, respectively. The results indicated that the middle and small flood with peak discharge varying within the range from 30000 to 55000 m³/s was the main form of the TGR flood in recent years. Flood regional composition tended to be controlled by both the lower reach of the Jinsha River and the Jialing River with an increase of the peak flood discharge. The inflow sediment was mainly consumed by sedimentation in the perennial backwater area and reservoir sediment discharge, and the former one had more considerable influence than the latter one. The increase of the initial water level Z₀ or the FRU operation affected the reservoir sedimentation by changing the siltation distribution firstly and decreasing the sediment delivery ration secondly in Case Ⅰ-3. The FRU affected the reservoir sedimentation little while Z₀≤150 m. While the ratio between the peak discharge of Wulong (Q'_WL) and the peak discharge of reservoir inflow (Q'_RK) was less than 1/5 (i.e. Q'_WL/Q'_RK<1/5) and the ratio between the peak discharge of Zhutuo (Q'_ZT) and the peak discharge of Beibei (Q'_BB) ranged from 3/2 to 3 (i.e. 3/2<Q'_ZT/ Q'_BB≤3) in typical flood event, an augment of the flood discharge would increase 50% of the inflow sediment, but the FRU increased less 5% of the water level (Z₀=145 m). As a result, sediment deposition in the fluctuating backwater area and sediment delivery to the reservoir downstream caused by the increasing discharge was more significant than those caused by the FRU. When the inflow sediment mainly comes from the Jialing River, sediment deposition becomes more considerable in the downstream channel of the confluence e between the Yangtze River and the Jialing River, and we should pay some attention to this phenomenon in reservoir operation and management.