In order to simplify the calculation of DC cable’s current capacity using the finite element method（FEM）

an equivalent two-layer structure of DC cable is presented to replace the ordinary structure and the equivalent thermal conductivity of the equivalent two-layer structure’s each layer is calculated to make sure that the equivalent structure could simulate the ordinary structure precisely. Based on the equivalent two-layer structure

the number of triangle elements of the finite element mesh could be decreased remarkably comparing with the number of elements of the ordinary structure’s finite element mesh. In the case study

the ordinary structure and the equivalent two-layer structure are applied respectively to calculate the current capacity of a specific DC cable（DC 200 k V YJQ41 1×1000+2×12 cable）with FEM. The results show that the two structures coincide with each other and they are consistent with the rated capacity given by the manufacture. Besides

a comparison between the computational demands of the two structures is performed. The result shows that the equivalent two-layer structure could dramatically simplify the calculation.