Soil salinization, a growing problem in arid and semi-arid areas, significantly influences the ecological dynamics and processes in wetland ecosystems. To fully examine the physiological responses with the aim of wetland protection and management, a laboratory simulation experiment was conducted to study the effects of soil salinization on the growth of C. schmidtii tussocks. Plant height and leaf traits, as well as physiological characteristics, were analyzed to explore the responses of C. schmidtii to soil salinization. Results showed that the highest value of electrical conductivity (EC) (4.71 mS/cm) recorded in 4000 mg/L treatment was 3.04 times greater than the lowest value (1.55 mS/cm) recorded in 0 mg/L treatment. It was well demonstrated that plant height under the 1000 mg/L treatment was 57.6% greater than that obtained under the 4000 mg/L treatment. Additionally, the growth of plants under the 4000 mg/L treatment achieved significantly higher length and the ratio of leaf withering (by 13.76 and 16.42 times, respectively), compared with those obtained under 0 mg/L treatment. 0 and 1000 mg/L treatments were found to greatly increase chlorophyll content and decrease malondialdehyde. Hence, slight salinization will stimulate the responses of C. schmidtii to environmental fluctuation, but the persistent serious salinization can inhibit the growth and physiology of C. schmidtii. The optimum ecological threshold of salinity for the growth of C. schmidtii was in the range 0~1000 mg/L. Results help in understanding the responses of C. schmidtii tussocks to soil salinization, and suggest the vital significance of preventing salinization in the Momoge Wetlands of northeastern China.