Investigating the historical processes behind crop phenology is essential for understanding crop response and adaption for climate change. Based on the 1990-2009 crop phenophase records from 46 agricultural meteorological stations in three provinces of northeast China, the maize phenophases (including the stages of seeding, maturity and length of the growth period) were extracted. The related annual slope change rates (θ) were then calculated and used to analyze the responses to temperature changes in the maize growing seasons of Northeast China during 1990-2009. The results showed that (1) over the past 20 years, positive trends of average temperature in May (T₅) and September (T₉), as well as an extended temperature-allowing period, were found in most areas of the three provinces. (2) With this background, various changes and responses had occurred in maize phenophases. Temporal trends of advanced seeding stage (0.02< θ < 0.15 d/a), postponed harvesting stage (0.18< θ < 0.38 d/a) and extended length of the growth period (0.22< θ < 0.44 d/a) were observed. It can be inferred the adaptive action by adjusting the early/middle maturing types to middle/late maturing types has been implemented to fully utilize the prolonged growth period under climate warming. (3) In response to the rising trend of T₅, advancing of the maize seedling stage occurred, which was most significant in the north of Songnen Plain, the middle and the east of Jilin and the middle of Liaoning. Corresponding to the rising trend of T₉, the maize maturity stage showed a postponement trend, which was more significant in the middle and east of Jilin. In response to the extending trend of the temperature-allowing period, the maize growth period showed an overall significant extending trend. Generally, the temperature changes during the crop growth period in Northeast China resulted in better temperature conditions for maize growth-especially for early-planting, late-harvesting varieties with a longer growth period. This may benefit future maize production, especially in northern areas. The findings provided implications for improving maize responses and adaptation studies, for researchers wishing to breed higher yielding maize cultivars and for enabling maize production to cope with ongoing climate change.