G-quadruplex is a unique secondary structure formed by four-stranded helical arrangements of DNA or RNA sequences rich in guanine. This structure is widely present at chromosome ends, gene promoter regions, and regulatory regions, participating in the regulation of gene expression, maintenance of chromosome stability, and protection of telomeres. G-quadruplexes play a role in various biological reactions and signaling pathways, such as transcription, replication, and DNA repair. Their formation is associated with specific gene expression patterns, and mutations or dysregulation may lead to the occurrence of diseases, such as cancer and neurodegenerative disorders. Therefore, G-quadruplexes are crucial targets for cellular function studies and disease treatment research.