The invention relates to the technical field of agriculture plantation and concretely discloses a chromosome doubling method for cotton growing points. The method comprises following steps of: (1) asexual reproduction of plants; (2) preparation of growing points to be doubled; (3) drying treatment of growing points to be doubled; (4) pruning processing of growth points; (5) reversing of growing points; (6) chromosome doubling processing of growing points; (7) post processing and other steps. The chromosome doubling method for cotton growing points has following beneficial effects: due to the fact that distant hybridization F1-generation plants are subjected to grating of growth points, seedling strengthening, drying, pruning, reversing, soaking of sleeve pipes, doubling and other whole set of doubling technology, processed growth points are easily permeated by colchicines so that time and labor are saved; chromosome doubling efficiency of growth points of plants is increased so that medicine resources are effectively saved; the risky problem of seed soaking and doubling operation is solved by avoiding sterility of distant hybridization F1-generation plants and shortage of seeds; and fertility is achieved after chromosome doubling operation so that a basis is provided for growth cotton and other rare plants.