Gleditsia sinensis Lam. (G. sinensis) as an important species within the Leguminosae family, has been utilized in Chinese medicine for centuries, and its thorns serve as a chief medicinal ingredient. The absence of a comprehensive genome database has hindered its in-depth research. In this investigation, a chromosome-level de novo genome assembly of G. sinensis 'Yulin No.1' was achieved, which harbors a 786.13 Mb sized genome with 36,408 protein-coding genes and experiences two WGD events. The comparative and evolutionary analysis unveiled the close phylogenetic relationship between G. sinensis and eight other Leguminosae species. The WGCNA and gene family analysis further indicated that GsinMYB was involved in the development of thorns. This investigation offered a high-level genome of G. sinensis, facilitating comparisons in Leguminosae species evolution and functional elucidation. It also provided key insights for further research on the molecular regulation mechanisms of thorn development in plants and the molecular breeding of G. sinensis.