Abstract: The yield potential of crops is closely related to variety and climate. Since 1950s there have been 4-5 variety renovations of winter wheat in China’s major wheat-growing areas, with significant climate change occurring in the same period. The confounding effects of climate and variety factors have not been separately investigated. This paper, taking Shijiazhuang as an example, estimated yield potential of five widely-used winter wheat varieties from 1955 to 2008 using the model DSSAT4.0 and the trends in accumulated temperature, solar radiation, and precipitation at four growth stages were analyzed to investigate the effects of climate change and variety improvement on wheat yield potential. The results showed that climate change was not uniform at different growth stages and had different impacts on wheat yield potential. Except sowing-reviving period, increasing trend of the accumulated temperature above 0℃ and decreasing trend of the solar radiation had significant negative effect on photothermal yield potential. Accumulated temperature during jointing-heading stage increased significantly, showing great influence on photothermal yield potential of the varieties bred before 1990s. And Solar radiation heading-maturity period decreased significantly, showing great influence on photothermal yield potential of the varieties bred after 1990s. Rainfed yield of all varieties was lower than photothermal yield potential and significantly affected by precipitation from reviving to maturity, indicating that water was the limiting factor in the region. Increasing of precipitation during reviving-jointing stage had significant positive effect on rainfed yield.