Coupling simulation was used in the buried seabed pipeline, to analyze the temperature field and stress field on the different leakage points. When the oil spilled to the sea mud area, it had the different influences on temperature field of the sea of mud, and there was a regular of distribution. When the leakage point was closed to the left and right sides of the pipe affected by gravity，the isotherm of leakage point moved down，the offside of leakage point moved up，the temperature field presented asymmetric distribution. When the leakage at the bottom of the pipes pressure field distribution was solely discussed, the isobar's distribution was symmetrical on both sides of the pipe, and gradually spread to the sides and top, and diffusion velocity had certain distinction with the leakage of buried pipe.

Due to the oilgaswater threephase flow is extremely complex, the threephase hybrid interface is weak of stability, different delivery conditions exist a variety of flow patterns. Using the VOF model simulation, the mock object was oilgaswater threephase flow in mutation tube, studying the fluid flow in pipe when the parameters(volume gas fraction, oil viscosity and velocity) was different, thus it gotten the corresponding phase distribution nephogram. Through analyzing the results showed that the gas volume fraction and velocity had great effect on mutiphase flow pattern. The effect of crude oil viscosity on flow patterns was not very obvious. The size of the pipe diameter also affected the flow pattern.

Based on computational fluid dynamic，a fluid solid coupling heattransfer model of submarine in two areas was built，which were respectively the area on seawater and the sea mud area，and the sea mud area was disposed of saturated silt porous. Using the software, the leakage during the process of transmission on naked placed hot oil pipeline was simulated, and the changes of distribution of crude oil in the soil and the water of the sea and the changes of the temperature field were analyzed，and different leakage points were analyzed respectively. The settlement of its own of the submarine pipeline on the naked place and the effect of the pressure in the sea water were considered in the simulation. The simulation results showed that different leakage points had a different influence on the distribution of crude oil|when the leakage in the sea mud area happened，the distribution of crude oil in the sea mud was a arcshape, after a period of time, the crude oil flowed into the sea long the sea mud and pipe insulation, and the top was a sprayshape and the flanks was helix, finally the crude oil flew onto the surface of the sea|when the leakage point was located in the sea area, oil was jet diffusion distribution form and under the action of buoyancy, the crude oil flow gradually onto the sea. As the leak position was different，the water of the sea and the sea mud there had significant differences in the distribution of temperature field. The interface of sea water and sea mud areas had a great impact on the temperature field distribution of crude oil.