The invention discloses a cotton boll increasing and protecting agent capable of solving the problems of the cotton falling, the cotton bud falling and the cotton boll falling and promoting a fallen bud to be reproduced. The active ingredients of the cotton boll increasing and protecting agent mainly comprise the raw materials in parts by weight: 0.1-1 part of indolebutyric acid, 0.01-0.1 part of naphthylacetic acid, 10-25 parts of paclobutrazol, 0.01-0.3 part of gibberellin, 0.1-5 parts of tiba, 10-25 parts of uniconazole, 0.1-1 part of indoleacetic acid, and 1-6 parts of amine fresh fat. The application test result of a planting test base shows that after the cotton boll increasing and protecting agent is used, compared with a blank test, the produced cotton of each plant is increased by 25, the bud and ball falling rate is decreased from 60% to 30%, the falling reproduction rate is increased by 8%, and the weight of each boll is increased by about 2.5%.