Background Sorghum is commonly used as feed in livestock farming. However, due to its high lignin and cellulose content, sorghum straw is not highly digestible for animals. To improve the feeding value of sorghum straw, researchers have explored micro-storage techniques. Enzyme preparation and straw expansion treatment are two commonly used methods, but their effects on sorghum micro-storage performance require further investigation.Results Sorghum exhibits relatively low nutritional value, but the addition of enzyme preparation and puffing treatment can enhance its value. These methods facilitate the breakdown of plant cell walls, releasing more nutrients and fermentable sugars, thus improving the digestibility and nutritional value of ensiled feed. Cellulase and xylanase can degrade cellulose and hemicellulose, respectively, which serve as important carbon sources for alkaligenic bacteria growth. Straw expansion treatment alters the proportions of lignin, cellulose, and hemicellulose in sorghum straw, leading to partial lignin degradation and an increase in organic matter content. The presence of lactic acid bacteria and alkaligenic bacteria enhances carbohydrate metabolism, amino acid, coenzyme, and vitamin metabolism, as well as signal transduction pathways, thereby improving microbial community structure, metabolism, and fermentation quality of ensiled sorghum feed. This study found that combined xylanase addition after expansion treatment significantly improves the micro-storage performance of sorghum straw. These findings provide a theoretical basis for optimizing sorghum straw micro-storage techniques to enhance its feeding value and animal production performance.Conclusions This study demonstrated that the addition of enzyme preparation significantly improved the quality of ensiled sorghum straw, with the best results achieved through the addition of xylanase. The sequential application of expansion treatment and enzyme addition yielded the best micro-storage performance for sorghum straw. These findings provide a theoretical basis for optimizing sorghum straw micro-storage techniques, contributing to increased feeding value and animal production performance. This study revealed, for the first time, the underlying principles of the synergistic effect between enzyme preparation and straw expansion treatment in the sorghum ensiling system, which provided valuable insights for the development and utilization of sorghum feed resources, and promotion of sustainable livestock production.