Drought is an important factor affecting the growth and development of maize. Therefore, identifying drought-resistant genes is vital for the genetic improvement of drought resistance in maize. In this study, the leaf rolling mutant swl5 (sensitive to water loss 5) was selected from the mutant library of EMS-mutagenized inbred line RP125. swl5 mutant exhibited a distinct leaf wilting and rolling phenotype under drought stress in the field. Map-based cloning revealed that the candidate gene was localized to a physical region of 280 kb on chromosome 5, which contains 9 coding genes. In this interval, a C-T mutation occurred at the 748th nucleotide of the GRMZM2G002260 gene, resulting in a premature stop codon. GRMZM2G002260 encodes the endo-1,4-xylanase gene ZmWI5. To further verify the gene function, the mutant wi5 of ZmWI5 was obtained. The F₁ plant derived from the cross of swl5 and wi5 mutant displayed the same leaf wilting and rolling phenotype as swl5 and wi5, indicating that swl5 is a new allele mutant of ZmWI5. Under drought stress, the swl5 mutant showed a significant drought sensitive phenotype, with photosynthetic rate, stomatal conductance, and transpiration rate significantly reduced compared to wild type (WT), while leaf temperature significantly increased, and the content of H₂O₂ and O_2- were notably elevated. The expression of genes involved in cellulose synthesis (CESA5) and xylan synthesis (DUF579, GT47, IRX9, IRX9H-1, IRX9H-2, GUX1, TBL33) was significantly down-regulated in the swl5 under both well-watered and drought stress. In summary, it is indicated that Swl5 encodes the ZmWI5 gene. The swl5 mutant exhibits a drought sensitive phenotype, and the expression of genes related to xylan synthesis is significantly reduced in the mutant.