Aiming at the problems of low ripening degree, poor soil fertility and urgent need to improve soil quality in the cultivated layer of newly-reclaimed high-standard farmland, a field positioning experiment was conducted from 2024 to 2025 to investigate the combined application of woody peat and nitrogen reduction (CK: 100% conventional nitrogen application 210 kg/hm2 without amendment; T1: 90% conventional nitrogen application 189 kg/hm2 + woody peat 4.5 t/hm2 + organic fertilizer 1.5 t/hm2 + activator 1.5 t/hm2; T2: 80% conventional nitrogen application 168 kg·hm?2 + woody peat 6.0 t/hm2 + organic fertilizer 2.0 t/hm2 + activator 1.5 t/hm2;T3: 70% conventional nitrogen application 147 kg/hm2 + woody peat 9.0 t/hm2 + organic fertilizer 3.0 t/hm2 + activator 1.5 t/hm2; T4: 60% conventional nitrogen application 126 kg/hm2 + woody peat 13.5 t/hm2 + organic fertilizer 4.5 t/hm2 + activator 1.5 t/hm2) on soil physicochemical properties and bacterial community structure in 0–40 cm soil layer of newly-reclaimed high-standard farmland in the Hexi Irrigation District. The results showed that: (1) Compared with CK, the combined application of woody peat and nitrogen reduction effectively reduced soil pH and electrical conductivity in 0–20 cm soil layer, and significantly increased the contents of soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available phosphorus (AP) and available potassium (AK) in both 0–20 cm and 20–40 cm soil layers, with the best improvement effect observed in T3 treatment. (2) Compared with CK, T3 treatment significantly increased phosphatase activity, sucrase activity, urease activity, catalase activity, microbial biomass carbon (SMBC) and microbial biomass nitrogen (SMBN) contents by 9.88% and 11.07%, 45.76% and 24.83%, 24.85% and 21.93%, 7.82% and 9.70%, 62.93% and 23.76%, 43.83% and 53.16% in 0–20 cm and 20–40 cm soil layers, respectively (P<0.05). (3) The dominant bacterial phyla in all treatments were Pseudomonadota, Actinomycetota and Acidobacteriota, and the dominant genera and families included Nitrososphaeraceae, Sphingomonas, Pyrinomonadaceae and Gemmatimonadaceae. The combined application of woody peat and nitrogen reduction significantly enriched beneficial functional microbes such as Pseudomonadota, Actinomycetota and Sphingomonas, while inhibiting the proliferation of Acidobacteriota, Pyrinomonadaceae and Gemmatimonadaceae, thus regulating the abundance distribution of dominant bacterial phyla. Soil organic matter, available nutrients, enzyme activities, MBC and MBN were the key environmental factors driving the variation of soil bacterial community diversity. Considering the improvement effect and cost comprehensively, T3 treatment is recommended for soil improvement of newly-reclaimed high-standard farmland in the Hexi Irrigation District, which can effectively ameliorate physicochemical properties, optimize microbial community and rapidly fertilize newly-reclaimed cultivated land.