Abstract: Based on the measured terrain data in different periods, this paper presents a comparative analysis on the general characteristics of siltation and its spatial-temporal distribution over the waterway in the Xiuying Harbor District, Haikou Port. We discuss the influencing factors and major causes of sediment accumulation in this waterway, predict the possibility and trend of severe siltation in future, and suggest engineering countermeasures for siltation reduction. We conclude with the followings. The spatial and temporal distribution of deposits over the waterway is non-uniform, spatially characterized by stronger siltation in its nearshore channel than open sea channel, and stronger in its channel sideline than mid-channel, and temporally characterized by a risk of strong short-term siltation. Its main causes are intrusion of the bottom sediment-water mixture with high concentration caused by heavy storm waves, transport of the side slope sediment into the channel, collapsing of side slopes, settling of suspended sediment in the water body, and construction of artificial islands. To reduce siltation, we suggest constructing sand-proof embankment, reducing the waterway side slopes, and increasing silting depth, among other engineering measures.