Conical tower drum for offshore wind power generation tower and machining method

The invention discloses a conical tower drum for an offshore wind power generation tower and a machining method, and the machining method comprises the following steps: cutting and blanking a conical drum section by adopting a numerical control cutting method, and controlling the cutting and blanking precision; welding grooves are formed in the conical shell ring; the welding grooves are formed in the two sides of the conical shell ring at the same time; the conical shell ring is rolled and fixed, specifically, the conical shell ring is rolled firstly, and then spot welding is adopted on a shell ring longitudinal seam formed after rolling for fixing; the longitudinal seam of the conical shell section is subjected to spot welding and then assembled with an upper flange and a lower flange; after the flange is assembled with the upper flange and the lower flange, the longitudinal seams of all the rings are firmly fixed, then the flange is placed on a roller carrier to be integrally welded, all the longitudinal c