In order to explore the effects of long-term different land uses on the colloidal complex and acidity of black soil, the soil colloid dispersion complex was extracted by colloid dispersion grouping method based on 10 pairs of long-term soil positioning sampling point (tillage black soil and shelterbelt black soil) in the black soil corn belt of Jilin Province. The results showed that the absolute contents of cultivated black soil and shelterbelt black soil increased in G₀ and G₂ groups, but decreased in G₁ group, and the total amount of complex decreased by 3.88% and 0.28%, respectively. The pH of cultivated black soil and shelterbelt black soil decreased by 12.12% and 3.77% respectively, and the contents of organic carbon in cultivated black soil and shelterbelt black soil decreased by 23.17% and 9.00% respectively. Humic acid, fulvic acid, exchangeable calcium ion and calcium carbonate decreased in the two land uses, and the average decrease in cultivated black soil was 12.18%, 3.53%, 16.29% and 31.53%, respectively. The black soil of shelterbelt decreased by 20.07%, 13.14%, 2.81% and 7.81%, respectively. The G₁ group showed extremely significant positive correlations with pH, HA, Ca²⁺ and CaCO₃, and significantly negative correlations with FA; while G₂ group had extremely significant negative correlations with pH, HA, Ca²⁺ and CaCO₃. Soil pH was significantly positively correlated with HA, Ca²⁺ and CaCO₃, and negatively correlated with FA. After 11 years, the stability of black soil colloid-dispersion complex decreased. Compared with non-tillage black soil, the stability of black soil colloid-dispersion complex decreased more seriously. The total amount of colloid-dispersion complex decreased more, and the acidity decreased more obviously than that of non-tillage black soil. The changes of Ca²⁺ and HA were the main driving factors affecting soil acidification and the stability of soil aggregates in black soil. As a result of soil acidification, the number of soil colloid-dispersion complex decreased and its stability became worse.