Jilin is among the most important grain-producing provinces in China. Its maize production plays an important role in local and national food security. In this study, we developed a new approach to assess the vulnerability and adaptation options for Jilin maize yields with respect to climate change by modifying a site-based biophysical model to a spatial grid-based application. An ensemble approach that used a combination of 20 general circulation model results and 6 scenarios from the Special Report on Emissions Scenarios was adopted in order to reflect the high uncertainties in future climate projections. The results show that the yield is highly likely to decline in the western and central regions of Jilin but to increase in the east, where maize is not currently grown as the main crop. Phenologically, the growing season will be reduced in the central and western parts, leading to a shortened grain-filling period. The average maize yield in the west and central regions is thus projected to decrease 15% or more by 2050 as predicted by 90% of 120 projected scenarios. In addition, CO₂ fertilization was investigated and demonstrated a noticeable compensation effect on the yield deduction. However, further field work and/or laboratory-based experiments are required to validate the modeled CO₂ fertilization effects. Two potential adaptation strategies, i.e. improving irrigation facilities and introducing cultivars, were identified from the vulnerability assessment and were further tested for the reduction areas. The results revealed that the increase in effective irrigation by upgrading the irrigation system would help to maintain the current production level, but in the long run, the maize cultivars need to be introduced in line with the future warming climate.