Abstract: In order to make clear the dynamics of photosynthetic performance of winter wheat during pre-winter period and the factors affecting photosynthesis, a determination was conducted using a photosynthesis measuring system in the fields of winter wheat with grain yield about 9t/hm2 for four varieties. The main results showed that, the dynamics of net photosynthetic rate (Pn), transpiration rate (TR) and stomatal conductivity (gs) of the leaf blades at different positions on the main stem for all varieties were similar. All the photosynthetic parameters above reached the maximum values at the beginning of determination or a little later, then decreased gradually. A sharp decrease leading to the lowest value of the parameters occurred owing to the first dramatic decrease of temperature. Recovery of the parameters occurred thereafter, but the Pn of leaves at higher position recovered more prominent than those of lower leaves, while the TR and gs of lower leaves recovered better. The dynamic tendency of Pn, TR, gs and the relevant ecological factors and correlation analysis showed that, Pn and gs of leaves during pre-winter period were affected by both temperature and PAR, but TR was cotrolled by temperature only. The synthetic performance of photosynthesis of the 3rd leaf was the best, then the 1st, 2nd and 4th in order, and the difference among these leaves mainly came from the difference of their leaf area.