Abstract: A warming climate trend in the last three decades has been well documented around the global and this trend have had a considerable impact on agricultural productivity. Phenology is a plant growth progress that is largely driven by meteorological conditions. Phenological changes are vital indicators for changes in climate and other environmental conditions. In this study, the trends in winter wheat phenology for 1981-2009 were investigated based on phenological dates from 16 agro-experimental stations in the North China Plain (NCP). The study showed that the dates of sowing, emergence and dormancy delayed. On the other hand, the dates of green-up, anthesis and maturity advanced in most of the stations. The advance or delay of winter wheat phenology resulted in corresponding changes in the durations of the different growth stages. In most of the investigated stations, the durations from emergence to dormancy, dormancy to green-up, green-up to anthesis and in the entire period from emergence to maturity of winter wheat shortened during 1981-2009. However, the duration of anthesis to maturity slightly prolonged on the average by 0.9 days per decade. Observed changes in winter wheat phenology were functions of both climate and management practices, especially that of cultivated cultivar shift. The effect of crop cultivar shift was isolated from that of climate change on winter wheat phonological changes by comparing field observed phonological events in four stations with those simulated by the CERES (Crop Environment Resource Synthesis)-Wheat model. The results suggested that climate warming played a dominant role in phenological changes in winter wheat in the NCP. However, the effect of cultivar shift on winter wheat phenological changes was not entirely negligible. Moreover, correlation analysis on the durations of green-up to anthesis and anthesis to maturity against mean temperatures for the growth periods showed that temperature increase by 1 ℃ shortened the durations of green-up to anthesis and anthesis to maturity by 3.8 and 1.2 days, respectively. Understanding the response of crop development and phenology to climate change was critical for not only building in-depth insights into the impacts of climate change on crop development and productivity, but also on food security for the millions of people in the region and beyond.