Abstract: In order to meet the needs of large scale and long distance transmission of offshore wind power, the research on the loss and temperature of three-core submarine cable under low frequency and twisted structure has become a key technical issues. Therefore, on the basis of simplifying insulation loss and environment boundary by analytic method, the electromagnetic-thermal coupling model of submarine cable under low frequency and twisted structure is constructed, and the loss characteristic and temperature distribution of the submarine cable are analyzed under the direct burial environment. The results show that the numerical model is effective by comparing with the analytic method based on IEC 60287 standard and previous simulation results. Reducing the operating frequency of submarine cable can improve the current distribution, reduce the loss and temperature, especially in inhibiting the insulation loss, sheath loss and armor loss. Reducing the twisting degree of submarine cable can improve the distribution of heat source, and reduce the loss and temperature per unit length of cable. With the decrease of operating frequency, the influence of twisting degree on cable loss and temperature tends to weaken, but cannot be ignored. The research results provide a technical basis for the refined design and performance optimization of submarine cable in offshore wind power grid connection project.