A field experiment was conducted in soda alkaline soil in the Hetao Irritated Area of Inner Mongolia to study the effect of different organic amendments on soil organic carbon (SOC) pool and chemical properties. Five treatments were designed as follows:traditional chemicals fertilizer only (CK), CK+biochar (BC), CK+cow dung (CD), CK+corn straw (SW), CK+goat manual (GM). Soil samples (0-30 cm depth) were collected after maize was harvested in 2019 and 2020, respectively, and the changes of SOC pool, labile organic carbon fractions, main saline and alkaline indexes and the relationship between them were analyzed. The results showed that compared with CK, the average increase of SOC in all organic amendment treatments were 22.7% and 17.2% in 2019 and 2020, respectively. The average increase in organic carbon stock (SOCs) were 22.9% and 18.2%, respectively. Labile organic carbon content increased in organic amendment treatments, among which the increase of CD and GM were higher than those in other treatments. CPMI increased by 53.8%~108.3% in organic amendment treatments compared with CK in 2019, and increased by 71.3%~144.1% in 2020 (P<0.05), and the promotive effect of CD and GM treatments was more obvious. As to the chemical properties, pH decreased apparently in four organic amendment treatments in 2020, exchangeable sodium percentage (ESP) decreased by 36.9% and 29.3% in BC and CD treatments, respectively (P < 0.05). Principal component analysis (PCA) showed that labile organic carbon fractions and ESP were the main factors which affected SOC content in soda alkaline soil. Cow dung and sheep manure had better effect on improving the quality of the organic carbon pool, and biochar had the most obvious effect on improving the chemical properties of soda alkaline soil.