Abstract: The accurate calculation of the current carrying capacity of submarine cables is a key technology to ensure the reliable operation of offshore wind power transmission systems. Based on the theory of multi physics field coupling, an 'electromagnetic-thermal-flow' coupling model for cluster three core AC submarine cables under direct burial and pipe laying conditions was established. The calculation accuracy and efficiency were balanced by optimizing the calculation domain size. Systematic research has shown that the current carrying capacity is significantly negatively correlated with burial depth and stably positively correlated with spacing; In environmental parameters, an increase of 5 ℃ in initial temperature results in a decrease of about 5% in current carrying capacity, while an increase of 1 K·m/W in soil thermal resistance leads to a decrease of 37% in current carrying capacity under direct burial conditions; The comparison of four arrangement methods shows that the current carrying performance of the straight shaped arrangement is the best, with an average improvement of 7% compared to the alternating shape, equilateral triangle, and inverted triangle. The research results can provide theoretical basis and engineering guidance for the optimization design of offshore wind power cluster cables.