PCMDB (Plant Cell Marker Database) is a database specifically constructed for plant cell marker genes. This database system collects and organizes various cell type-specific marker genes of multiple plant species, covering different tissues and developmental stages such as roots, stems, leaves, flowers, and fruits. PCMDB provides reliable cell type annotation references for plant single-cell transcriptome research, helping researchers quickly identify and verify cell identities, and is an important infrastructure for plant single-cell biology research.