Using spacetime substitution method, we investigated and analyzed the vegetation succession characteristics, changes in soil enzyme activities and their correlations for different years of abandoned land (returned fields 1 a, 2 a, 4 a, 8 a, 13 a, 20 a, 30 a, 40 a) in Minqin Qingtu Lake, farmland as control (CK), to explore the correlation between vegetation communities and soil enzyme activities, To reveal its change pattern and its driving mechanism, and to provide a scientific and theoretical basis for the restoration of receding farmland ecosystem and ecological environment construction in Qingtu Lake area and its similar areas. The results showed that: (1) Qingtu Lake during the natural recovery process after 40 a of fallowing, a total of 42 species, 32 genera and 16 families were found in 9 quadrats, the species composition is as follows: most species belong to a few families, and most species belong to a single genus and family. (2) With the increase of the period of returning farmland, plant species decreased from 19 species at the beginning of fallowing (1 a or 2 a) to 14 species at 4 a, 13 species at 20 a, and 5 species at 30 a. The salinetolerant shrub plant salt claw became the dominant species in this area at 30 a of fallowing, with a maximum importance value of 52.862.The importance value of the dominant species salt claw decreased to 36.008 at 40 a of fallowing. (3) With the increase of the period of returning farmland, there is a fluctuating downward trend in the plant Margalef richness index. The overall trend of Shannon diversity index and Pielou evenness index increased first, then decreased, and then gradually stabilized. Simpson dominance index has a small change range and a stable trend. (4) The activities of the four kinds of soil enzymes in different soil layers (0-20 cm and 20-40 cm) increased firstly, then decreased and then gradually stabilized with the increase of returning years. All decreased significantly after 8 a of farmland withdrawal, and phosphatase activity and urease activity were significantly lower than sucrase activity and peroxidase activity. Both phosphatase activity and urease activity decreased with increasing years of fallowing compared to the control sample plot (CK). Soil phosphatase, sucrase and urease activities all decreased with deepening of the soil layer. (5) Correlation analysis showed that, in the 0-20 cm soil layer, the number of species was significantly and positively correlated with soil sucrase activity, phosphatase activity and urease activity; in the 20-40 cm soil layer, the correlation between the number of species and soil urease activity was extremely significant and positive, while it was significantly negatively correlated with soil peroxidase activity. Margalef richness index was significantly and positively correlated with both phosphatase activity and sucrase activity in the 0-20 cm soil layer, and was highly significantly and positively correlated with urease activity; in the 20-40 cm soil layer, Margalef richness index was extremely significantly positively correlated with urease activity. The correlations between Shannon diversity index, Pielou evenness index and Simpson dominance with the four soil enzyme activities were low and none of them were significant. The research suggests that Qingtu Lake during the natural recovery process of 40 a of fallowing, the plant community became relatively simple, and the species diversity decreased year by year, urease activity played a key role in species diversity.