Abstract: With the increasing transmission distance of offshore wind farms, the economy of submarine cable has gradually attracted attention. In order to increase the economy of submarine cable, COMSOL finite element simulation software was used to calculate rated current-carrying capacity of submarine cable. Methods to increase rated current-carrying capacity of submarine cable were put forward from the aspects of increasing conductor cross-sectional area, changing armor mode and optimizing laying process. Results showed that when the submarine cable was armored with galvanized steel wire, there was a negative correlation between the number of armored cables and rated current-carrying capacity of submarine cable. Non-magnetic stainless steel wire armor had a small gain on rated current-carrying capacity of submarine cable, usually 1.7%~2.0%. The gain of copper wire armor to rated current-carrying capacity of submarine cable was more obvious. When cross-sectional area of 220 kV submarine cable was 1800 mm², rated current-carrying capacity of the copper wire armor increased by nearly 17% compared with galvanized steel wire armor.