Abstract: The accumulation and distribution characteristics of various solutes from Kochia sieversiana seedlings stressed by salt and alkali were measured to study the physiological mechanisms in different parts of K. sieversiana and their role in adaptability to salt-alkalinized soil, and to identify the contribution of organic acid to salt-alkalinized habitat adaptability. There were considerable differences in the distribution of various solutes from different plant parts such as young leaves, mature leaves, young stems, old stems and roots. Organic acid was distributed mainly in stems and leaves, especially in mature and functional leaves on which photosynthetic productivity was dependent. Distributions of Na⁺, K⁺ and Ca²⁺ in different plant parts were uniform on the whole indicating that there was no competition for Na⁺, K⁺ and Ca²⁺ for absorption and transportation. Special absorption mechanisms of K⁺ and Ca²⁺ and distribution characteristics of various solutes from K. sieversiana were very important to its adaptability to salt-alkalinized soil. Organic acid in different parts, especially in mature leaves of K. sieversiana, was the dominant element in osmotic regulation, ion balance and pH adjustment, and was a key substance for the adaptation to saline and alkaline conditions. There were different adaptive mechanisms to salt and alkali stresses in different parts of K. sieversiana plants.