Abstract: The present disclosure discloses a method for producing raw cotton of machine-harvested long-staple cotton with a modal length of greater than or equal to 35 mm, including the steps: planting sea-island long-staple cotton and machining seed cotton, wherein planting the sea-island long-staple cotton includes preparation before machine harvesting, defoliation and ripening, choosing a cotton variety, etc.; and machining the seed cotton includes preparation before seed cotton ginning, mechanical separation of cotton seeds and raw cotton, and finishing the separated raw cotton. Raw cotton fibers obtained by the method of the present disclosure have main quality indexes that: a fiber length is 36.5-38.4 mm, a specific strength is 42.3-46.1 cN/tex, a uniformity is 86.2-87.0%, a foreign-fiber content is 0.2-0.4 g/t, and an impurity content is 2.6-3.4%.