［Obiective］Chitinases belong to the glycoside hydrolase family and play a crucial role in plant growth and stress responses by hydrolyzing chitin. This study aims to genome-widely identify the chitinase gene family in sorghum， analyze its genomic characteristics and evolutionary patterns， and investigate the expression profiles of this gene family under aphid stress by integrating public transcriptomic data and independently performed quantitative reverse transcriptase-mediated PCR（qRT-PCR） experiments. This work will fill the research gap regarding the response of the sorghum chitinase gene family to sugarcane aphid （Melanaphis sacchari） stress， and provide candidate genes for molecular breeding of aphid-resistant sorghum.Method In this study，42 sorghum chitinase genes （SbChi） were identified using bioinformatics approaches. Their physicochemical properties，chromosomal locations， gene structures， evolutionary characteristics， and cis-acting elements were systematically analyzed. The expression patterns of the SbChi gene family under aphid stress were further validated by integrating RNA-seq data and qRT-PCR experiments.Result These 42 SbChi gene family members contain two domains （GH-18 and GH-19） and are classified into 5 subfamilies， which are unevenly distributed on 9 chromosomes of sorghum. Among them， 3 pairs of genes underwent segmental duplication， with divergence times of approximately 40.60， 40.84， and 81.49 million years ago， respectively. Most SbChi proteins are acidic proteins. Prediction of cis-acting elements reveals the presence of numerous stress-responsive elements， mainly involved in hormone responses and growth and development regulation， indicating that this gene family is primarily involved in stress resistance. With published RNA-seq data， differential expressions of the SbChi gene family between resistant and susceptible sorghum varieties have been found. qRT-PCR analysis confirms the relative expression characteristics of SbChi gene family members under aphid stress.Conclusion The results of this study provide new insights into clarifying the potential functions of the SbChi gene family in biotic and abiotic stress responses， and lay a theoretical foundation for analyzing the molecular mechanism of sorghum adaptation to stressful environments.