To reveal the distribution characteristics of stress and strain, load characteristics, and influence mechanism of super-long and large-diameter steel casings during the construction process in deep-sea areas, the dynamic stress and strain of the casing body were dynamically monitored during the static pressure construction of the steel casing in deep-sea areas in this paper to calculate the stress distribution of the steel casing; meanwhile, finite element simulation was conducted using Abaqus software to analyze the variation characteristics of pile top load, side friction resistance, and end resistance during the static pressure process of the steel casing on the inclined rock surface of the seabed. The research results indicate that: ① In the initial pressing stage, the overall deformation of the steel casing is relatively large, and the average strain rates are 40 × 10^?6/h and 56 × 10^?6/h, respectively, indicating significant overall deformation; in the counterweight pressing stage, affected by the pile end resistance, the average strain rate increases from 2.5 × 10^?6/h to 28 × 10^?6/h. The development of the pile top load and side friction resistance determines the magnitude of the end resistance; ② Affected by the thin-wall effect, the axial force of the above-water and underwater sections of the steel casing is unevenly distributed, with the upper axial force gradually increasing, the middle part remaining unchanged, and the lower part gradually decreasing; ③ The side friction resistance of the steel casing is related to soil parameters and penetration depth. In the initial stage, the side friction resistance is greatly affected by the penetration depth, and with the increase of depth, soil parameters become the main factor. The research conclusions can provide a theoretical basis for the design and construction of super-long and super-large steel casings for deep-sea engineering under similar construction environments.