Saline-alkali soils constrain dryland agriculture through high salinity, poor structure and low fertility. Interlayers can regulate soil moisture and salt, improve soil nutrients and alter microbial communities. However, little is known about how soil pore structure, microbial co-occurrence networks and assembly processes in respond to straw and sand interlayers in saline-alkali soil. A novel straw-sand interlayer system applied at 40 cm depth (treatments: JG=5 cm straw; SC=5 cm sand; JS=2.5 cm sand + 2.5 cm straw; CK=control) was assessed in a twoyear field study. The results showed that integrated straw-sand interlayer increased topsoil (0-40 cm) moisture by 10-12 % after irrigation and reduced salt content by 15-36 % after harvest. Compared with CK, JG and JS treatments significantly elevated soil organic carbon, total nitrogen, available nitrogen, phosphorus, potassium within the 0-60 cm layer. Additionally, interlayer treatments enhanced total soil porosity by 74.3-247.4 % relative to CK. Interlayer treatments also increased the abundance of Acidobacteriota and Ascomycota and complexity of microbial co-occurrence networks, while decreased the abundance of Proteobacteria and Basidiomycota relative to CK treatment. Partial Least Squares Path Modeling demonstrated that soil nutrients and pore structure were primary drivers of yield enhancement under interlayers, with bacterial and fungal networks also exhibiting vital role in improving sunflower yield. Overall, this study demonstrated that interlayers enhances crop yield by regulating soil moisture & salt, nutrients, pore structure and microbial networks-with combined straw and sand interlayer showing the most pronounced effect on crop yield enhancement in saline-alkali soils.