The Volume of Fluid (VOF) soil-water two-phase flow model is used in combination with the SST k-ω model and Herschel-Bulkley model to develop a two-dimensional numerical model of the local erosion of a submarine pipeline to model the erosion of a clay submarine pipeline. By comparing and studying the local erosion profile, lift coefficient, maximal depth of erosion pits, etc. of the pipelines, the impact mechanism of different installation positions and lengths of the spoiler on the pipeline erosion characteristics is analyzed. The results show that: the spoiler installed directly above the pipeline intensifies the local erosion, and the maximal depth and width of the local erosion pits of the pipeline increase as the spoiler length increases; the spoiler installed behind the pipeline and parallel to the inflow direction helps to suppress the local erosion, reducing the maximal depth and width of the erosion pit; the bidirectional rigid spoiler installed at the bottom of the pipeline is effective in preventing the local erosion, when the length of the bidirectional rigid spoiler is 3D or more, the local erosion of the pipeline essentially does not occur.