The environmental response of plant net photosynthetic rate and leaf traits has great significance to understanding the relationship between the physical structure and physiological metabolism of plant leaves under different habitat conditions. There were two main goals in this study:(1) To evaluate the relationship between the net photosynthetic rate and leaf characteristics of Phragmites australis in different soils; (2) to determine the main reasons for this relationship. The study site was located in the national wetland park conservation areas in Jiayuguan city, Gansu Province, China(39°54'10.55″-39°56'42.26″ N, 98°25'56.98″-98°29'25.23″ E). The sample area was divided into three levels based on the variation rule of groundwater depth and surface water level in reed populations:I (groundwater depth:0.3-0.6 m), Ⅱ (groundwater depth:0-0.3 m), Ⅲ (surface water level:0-0.3 m). According to the "Z" order curve, six (2×2 m) reed samples were selected per plot, for a total of 18 samples (3×6). Then, community traits (height and aboveground biomass), soil moisture and soil electrical conductivity (EC) were determined and six individuals of P. australis were taken to the laboratory to measure the leaf thickness. In addition, the leaf net photosynthetic rate (P_n), transpiration rate (T_r) and other parameters of the reeds were measured in each plot. Quadrat survey methods were used to determine the relationship between the net photosynthetic rate and leaf traits of the reeds. The results indicated that, with the increase of soil moisture, the wetland community height gradually increased, as well as the coverage, aboveground biomass, leaf area and net photosynthetic rate. However, the leaf thickness and soil EC gradually decreased. A highly significant negative and positive correlation (P < 0.01) between P_n and LA at height and low moisture(I, Ⅲ) was observed, respectively. There was a significant positive correlation between P_n and LA and only a significant negative correlation between P_n and leaf thickness(P < 0.05) at medium moisture(Ⅱ). With the increase in soil moisture, the reeds selected the strategy of increasing the leaf area and reducing the leaf thickness, and the P_n correspondingly increased, which reflected the malleable mechanisms of plant populations adapting to their habitat.