Abstract: Based on the framework of logistic equation, a crop model considering the after-effect of water stress was established. It was then used to simulate the dry matter accumulation of shoot and root of winter wheat. Comparison between the simulated and the measured value showed good agreement between them, indicating the correct model structure. The model can simulate not only the process of monotonic rise as shoot growth, but also the process of first rise and then down as the root growth, suggesting its general applicability. It contains both time-constant and time-dependent parameters that have clear practical meanings. Comparative study on the time-dependent parameters of shoot and root showed that the water stress had greater after-effect on shoot growth than on root growth, suggesting the more sensitive growth process to water stress was affected to a larger extent by after effect.