The comprehensive database of single-cell transcriptomics annotation resources (CellSTAR) was constructed to (a) offer the comprehensive expertly annotated Reference Data for annotating hundreds of cell types for the first time, and (b) enable the collective consideration of Reference Data and Gene Markers by incorporating tens of thousands of markers. Given the rapid advances of AI in single-cell omics, CellSTAR is expected to have significant impact on understanding cellular heterogeneity, developmental biology, disease research, drug discovery, etc.