In order to provide bases for determining the operating limits of DC cable lines and the dynamic regulation of operating margins, 1 h、1.5 h and 4 h dynamic current-carrying tests of 160 kV DC cable were carried out, and the variation of DC cable conductor, lead encasing and armor temperature with overload time were obtained. At the same time, the finite element simulation software Comsol Multiphysics was used to establish the transient thermal field model of the ±160 kV DC submarine cable, thus simulating the cable temperature under different emergency load conditions. Additionally, the reliability of the simulation model was verified by combining the experimental data, and the influence of the thermal conductivity of each part of the DC cable on the simulation results was also analyzed in detail.