[Objective] The study aimed to investigate the response of cotton phenophase to climate change in Hebei Province. [Method] Using 1981-2010 cotton phenophase and meteorological data from agricultural meteorological experimental stations and meteorological stations in Hebei Province, China, we analyzed trendsin climatic factors, cotton phenophase, and the timingof different cotton developmental stages. We also calculated Spearman coefficients between the days of different cotton developmental stages and meteorological factors at typical stations in Hebei Province. [Result] We observed the following results over the investigated timeframe: 1)In Hebei Province, T_(mean) and accumulated temperature ≥0℃ increased during each cotton developmental stage. 2)Sowing, emergence, squaring, flowering and boll-opening phenophases advanced, but harvesting was delayed. Consequently, developmental stages prior tothe flowering phenophase were shortened, whereas those after flowering were lengthened. The entire developmental period was therefore extended. 3)Prior to boll opening, T_(mean) and accumulated temperature ≥0℃ at each developmental stage were negatively correlated with the length of different developmental stages. After boll opening, however, T_(mean) andaccumulated temperature ≥0℃ at each developmental stage as well asover the entire period of development were positively correlated with developmental stage length. [Conclusion] This research, which helps explain the mechanisms underlying the impact of climate change on cotton growth and development, can aid the development of technologies and strategies for adaptation of cotton production to climate change.