Small RNAs (sRNAs) are essential for regulating plant growth and development, and they possess the notable ability to travel long distances within organisms to regulate target gene expression. Our study examined the dcl2 mutant, a key enzyme in sRNA biogenesis, to determine the role of the DCL2 protein in sRNA synthesis and to identify mobile sRNAs under DCL2 regulation. Through grafting experiments between dcl2 mutants and wild-type soybean plants, coupled with sRNA sequencing, we identified 14,105 sRNAs significantly affected by DCL2 and discovered 375 mobile sRNAs under its regulation. Degradome analysis provided deeper insights into the regulatory effects of these mobile sRNAs on their target genes, enabling us to understand their potential influences on plant development and stress responses. Leveraging the systemic movement of sRNAs from roots to shoots, we propose a novel strategy for manipulating gene expression in aboveground tissues. Overall, our research findings not only deepen our understanding of the complex regulatory networks involving mobile sRNAs regulated by DCL2, but also provide a new strategy for gene regulation, which could have a positive impact on agricultural biotechnology.