Abstract: A series of winter wheat varieties in different decades is selected for measuring the leaf photosynthesis under suitable soil moisture and temperature conditions. The light response curves are fitted for each variety, and the initial quantum efficiency, maximum photosynthesis rate and respiration rate are determined. The variation regularity of leaf photosynthesis parameters with time is revealed based on these characteristic parameters. Numerical analysis of the effects of the initial quantum efficiency and maximum photosynthesis rate on the daily photosynthesis shows that it is not suitable to quote parameters from foreign literatures as the basic parameters in the Chinese crop models. A set of basic parameters of the crop model is presented, which provides premise for simulating the regional application with crop models in the future.