The invention discloses a large-section EPR insulated direct-current flexible cable for wind power and a production process thereof. The large-section EPR insulated direct-current flexible cable for wind power sequentially comprises a central wire core, a main conductor, a main insulating layer and an outer sheath from inside to outside, wherein the central wire core sequentially comprises a central insulating filling strip, central conductors, a central wrapping tape and a central insulating layer from inside to outside; the main conductor comprises a plurality of branch conductors which arestranded and wrapped outside the central wire core, a semi-conductive belt wrapped outside the branch conductors and semi-conductive filling strips filled in external gaps of the adjacent branch conductors. According to the invention, a plurality of branch conductors are stranded and wrapped outside the central wire core, thereby not only ensuring a large sectional area of the cable, but also reducing the number of the conductors. The arrangement of the central wire core balances the electric field, so that the overall current-carrying capacity is large, and the safety is high.