Abstract ：The effects of five different biochar dosages (0%, 0.5%, 1.0%, 2.0%, and 4.0%) on soil physicochemical properties, bacterial community structure and function, and the growth of cabbage in newly reclaimed field were investigated. Cabbage was used as the test material for this study, and potting tests and high-throughput sequencing technology were employed. The results revealed significant variations in cabbage growth and soil physicochemical properties among the treatments. Specifically, the B10 treatment significantly increased cabbage plant height, aboveground biomass, root weight, as well as soil organic carbon, total nitrogen, available potassium content, pH, and CEC. Additionally, the B10 treatment significantly reduced the root-crown ratio of cabbage. The different biochar treatments (B5, B10, B20, and B40) significantly increased the Alpha diversity indices of soil bacterial communities, including Chao 1, Observed species, Shannon. Notably, these bacterial diversity indices exhibited significant positive correlations with aboveground biomass, root weight, soil organic carbon, total nitrogen, available potassium content, pH, and CEC. The application of biochar can significantly modify the structure of soil bacterial communities by influencing soil properties such as cation exchange capacity (CEC) and pH. Both the bacterial communities and their metabolic functions are strongly associated with aboveground plant biomass and the shoot-to-root ratio. As biochar application rates increase, the number of key indicator species that contribute to variations in soil bacterial communities also rises, with many of these species showing significant correlations with cabbage growth metrics. In the B0 treatment, the dominant indicator species are predominantly from bacterial groups such as Bacteroidia and Pseudonocardiaceae. In contrast, the indicator species in biochar-treated soils are mainly copiotrophic bacteria belonging to the phyla Acidobacteriota, Actinobacteriota, Chloroflexi, Myxococcota, and Proteobacteria. Specifically, in the B10 treatment, the dominant indicator species are Chitinophagales and Blastocatellia, while in the B40 treatment, they mainly consist of Alphaproteobacteria, Burkholderiales, and Rhizobiales. .Moreover, biochar treatment had a significant impact on the metabolic functions of soil microorganisms in terms of amino acids, carbohydrates, and lipids. The B10 treatment notably increased the metabolic functions of amino acids and lipids while significantly decreased the metabolic functions of carbohydrates. In conclusion, the application of biochar can improve the physicochemical properties of newly reclaimed soil, enrich the bacterial community, and promote crop growth. Considering the cost of application and the amelioration effect, it is recommended to use a biochar dosage of 1.0% on newly reclaimed field.