In this paper,a cotton(Gossypiwm hirsutum L.)growth and development model is established, according to field experimental data of 1984 and 1985. Net photos-ynthetic production is calculated according to light radiation, leaf area index, dry plant weight etc. , and is distributed to the organs . Mainstem nodes are predicted by using physiological time. The numbtrs of fruiting branches and fruiting sites are determined by the synchrosequence of terminal bud and axillary buds. The following logistic curve is p...