In order to find the best organic fertilizer and inorganic fertilizer, the material used in the experiment was winter wheat 9801, cultivated by Shanxi Agricultural University. The experiment was carried out in the experimental field of Shanxi Agriculture University with 2 low nitrogen (270 kg·hm²) and high nitrogen (360 kg·hm²) application rates of inorganic fertilizer and organic fertilizer for each of the 37 500 kg·hm²、75 000 kg·hm²and the application of the 4 organic fertilizer inorganic fertilizer combined with a total of 6 treatments, the effects on group leaf area index、population structure、chlorophyll content and photosynthetic characteristic under a certain amount of nitrogen fertilizer mixed application of organic and inorganic fertilizer were studied. The result show that: the leaf area index was maximum when total nitrogen was high nitrogen condition, organic fertilizer was 75 000 kg·hm²,inorganic fertilizer was 228.3 kg·hm²; when total nitrogen was under low nitrogen condition, organic fertilizer was 75 000 kg·hm²,inorganic fertilizer was 32.6 kg·hm², the group structure were most reasonable; the flag chlorophyll content and the flag net photosynthetic rate were maximum. On the whole, the optimum value of experimental groups  total nitrogen was under high nitrogen condition, organic fertilizer was 75 000 kg·hm²、inorganic fertilizer was 228.3 kg·hm²( F group ).