Exploring the effects of climate change on cotton phenology and yield could stimulate economic development and forecast cotton yield under future climate warming. In this study, a field warming experiment involving infrared radiators was conducted to investigate the responses of cotton phenology and yield to climate warming. A 0.6 ℃ rise of soil temperature was shown to advance the flower and boll stage by 3 days, and to extended the entire growth stage by 2 days. Warming also profoundly enhanced the leaf net photosynthetic rate at the flower and boll stage, and boll opening stage by 5.4% and 14.7%, respectively. During the growing stage, warming significantly increased the mean square and boll number of cotton by 7.4% and 7.2%, respectively. It also remarkablely enhanced the total plant biomass and distribution coefficient of the boll biomass by 32.2% and 11.0%, respectively, at the maturity stage, and significantly increased the boll mass per plant and above ground biomass per plant by 30.4% and 38.1%, respectively. Finally, warming also stimulated the cotton yield by 23.6%. This study suggests that climate warming may facilitate cotton yield in the region of the middle and lower reaches of the Yellow River.