In order to gain more insight into the effect planting patterns on increasing yield and efficiency of winter wheat. In our study, the effect of wide uniform planting and conventional planting pattern with the same row spacing on the photosynthetic characteristics, sucrose supply level and antioxidant enzyme activity of flag leaf were studied in field trails, using winter wheat "Lantian26" as materials. The results showed that the dynamic changes of net photosynthetic rate（Pn） and photosynthetic active duration（PAD） of flag leaves were significantly increased during the middle and late grain filling period, and the duration of Pn high value and relative stability of chlorophyll SPAD value（RSP） were prolonged respectively by 6.1 d and 5.2 d under the wide uniform planting compared to the conventional planting with the same row spacing. Wide uniform planting reduced the intercellular CO₂ concentration（Ci）,stomatal conductance（Gs） and transpiration rate（Tr） in the later stage of grain filling. Moreover, the extended steady phase of chlorophyll content and the increased photosynthetic active duration in flag leaf might decelerate the aging of flag leaf, which could significantly increase its photosynthate supplying duration. Compared to the conventional planting with the same row spacing, both sucrose phosphate synthetase（SPS） activity and sucrose supplying capability of flag leaves in winter wheat under the wide uniform planting were significantly increased during the grain filling period. The results indicated that compared to wide uniform planting,the SOD and CAT activities were higher than that of the conventional planting with the same row spacing during the grain filling period, and the peak was reached 5 days earlier, the rate of decline was slow, the duration of high value was longer, while the superoxide dismutase was only higher in the late stage of grain filling period. So the lipid peroxidation level was improved,and then the flag leaf senescence was decelerated. The thousand kernel weights and yield were 5% and 9.1% higher under wide uniform planting than under the control. There was no significant difference in the number of productive ear and the kernel number between wide uniform planting and the control. Protein content, wet gluten content, sedimentation value and dough stability time were increased by 11.9%, 9.6%, 11.7% and 13.7% higher under the conventional planting pattern. Therefore, the flag leaves of winter wheat under the wide uniform planting can maintain a relatively higher photosynthate supplying rate, longer photosynthate supplying duration, lower reactive oxygen producing rate and lower lipid peroxidation level, which could be a key reason for a higher quality and yield.