In order to understand the construction pattern of Phragmites australis under different water gradients in arid wetlands and to show significant differences in its adaptability to different water environment, the response of this reed's leaf traits to different soil moisture levels was studied in Dunhuang Yangguan Wowachi wetland. The results showed that:(1) The leaf thickness (LT) and leaf phosphorus content (LPC) in reeds growing in soils with low moisture levels was significantly higher than those growing in soils with medium and high moisture content, and the leaf carbon content (LCC) in high soil moisture areas was significantly higher than those growing in soils with medium and low water content. (2) Also, the relationship between the leaf characteristics of this reed differed with the soil moisture content. As a whole, the LCC was significantly negatively correlated with the leaf dry matter content (LDMC) (P < 0.01), and the LT was significantly positively correlated with the LPC (P < 0.01). The specific leaf area (SLA) was significantly positively correlated with leaf nitrogen content (LNC) (P < 0.01), and significantly negatively correlated with the leaf carbon nitrogen ratio (C/N) (P < 0.01). (3) When water was a limiting factor, for SLA, the response of LCC to soil moisture was the most prominent. Soil water content was significantly negatively correlated with LT, LCC, and LPC (P < 0.05). Phragmites australis adopts a high-income and low-input active survival strategy in a low-moisture environment, and adopts a low-capacity, high-consumption, conservative survival strategy under high water conditions, indicating the self-regulation mechanism of this reed in adapting to heterogeneous habitats.