In response to the problems of poor soil quality and increasingly severe salinization in Lanzhou New Area, field experiments were carried out from 2022 to 2023 to explore the effects of 2 types of crops (C1: Sainfoin, C2: Wheat) and 3 soil improvement methods (A0: traditional fertilization, A1: 9.0 t/hm2 woody peat + 3.0 t/hm2 organic materials + traditional fertilization, A2: 7.5 t/hm2 desulfurized gypsum + 3.0 t/hm2 organic materials + traditional fertilization) on the physical and chemical properties, nutrient contents, enzyme activities, microbial carbon and nitrogen (MSBC and MSBN) of the 0-30 cm cultivated layer of saline-alkali soil in Lanzhou New Area, as well as the crop yields. The results showed that: (1) Compared with A0, the addition of woody peat and desulfurized gypsum could effectively reduce the soil bulk density, pH value and water-soluble salt content, and increase the contents of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), nitrate nitrogen (NO??-N), ammonium nitrogen (NH??-N), available phosphorus (AP), and available potassium (AK). The treatment combinations of C1A1 and C2A1 had more obvious effects, but there was no significant difference between them. (2) Compared with A0, the activities of soil invertase, urease, catalase, alkaline phosphatase, and the contents of MSBC and MSBN in the treatment combinations of C1A1 and C2A1 were significantly increased by 24.74% and 23.61%, 49.48% and 48.14%, 71.32% and 69.77%, 38.37% and 35.93%, 29.54% and 29.68%, 106.26% and 112.51% respectively (p<0.05). (3) The order of soil quality index (SQI) was: C1A1 (0.68) > C2A1 (0.64) > C1A2 (0.56) > C2A2 (0.54) > C1A0 (0.40) > C2A0 (0.37). The order of the biomass of Sainfoin straw was: C1A1 > C1A2 > C1A0. The order of the biomass of Wheat straw and the grain yield was both: C2A1 > C2A2 > C2A0. There was a significant positive correlation between SQI and crop yield (the R2 values of the biomass of Sainfoin straw, the biomass of wheat straw and the grain yield were 0.9338, 0.9687 and 0.9610 respectively, p<0.05). In conclusion, for the improvement of saline-alkali soil and the enhancement of soil fertility in Lanzhou New Area, the improvement mode of A1 is recommended.