In order to study the influence of different solidified soil protection thickness on the protection effect on suction cylinder foundation, Flow-3D is used to establish a calculation model for the suction cylinder foundation with a diameter of 10 m, and combined with the silt curing mechanism the influence on the anti-washout characteristics of the suction cylinder foundation under the conditions of 0 m, 0.4 m, 0.6 m protection thickness of the solidified soil at different flow speeds is comparatively analyzed. The results show that: there is an obvious positive correlation between the protection thickness of solidified soil and the protection effect, and the maximal protection effect of 0.6 m thickness can be improved by 66.47%; the development curve of the scour depth is approximately in the shape of a logarithmic curve, the slope of the growth curve is the largest in about 1 200 s, and the equilibrium is reached earlier in the thickness of 0.6 m than in the thickness of 0.4 m; the relationship of the protection ratio between different protection thicknesses is introduced, and it is found that the thickness of the solidified soil protection for the suction cylinder foundation with diameter of 10 m and above should not be less than 0.4 m. The conclusions can be used as a reference for the same kind of scour protection project and engineering design.