Objective To generate a comprehensive transcriptomic profile of cellular signifures and transcriptomes of human placenta in GDM by single-cell RNA-sequencing (scRNA-seq), and built a comprehensive cell atlas. We hope to reveal the molecular mechanism of pregnancy risk for GDM women. Design Scientific study. Setting University Hospital and laboratories. Population or Sample Pregnant women Methods 20 GDM women and 20 normal pregnant women were recruited in present study. ScRNA-seq were loaded on the Chromium Single Cell Controller Instrument (10×Genomics) to generate single cell gel beads in emulsions (GEMs). Results A total of 27,220 cells from placenta samples were obtained. First, with the cell-type-specific marker genes, we annotated 15 cell clusters into more than 9 different cell types. Second, beside the classcial markers, we also found some novel markers for distinguishing three kinds of trophoblast and subtypes, which cloud be confirmed by immunohistochemistry imaging. Third, we demonstrated the specific placental function in GDM by the bioinformatics analysis of differentially expressed genes, such as estrogen signaling pathway, natural killer cell mediated cytotoxicity down- regulated. Fourth, there are abundant ligand-receptor interactions between trophoblast and immune cells in the maternal fetal interface microenvironment, such as VEGFB-FLT1, MIF-EGFR, RPS19-C5AR1, SPP1-CD44These dysfunctional ligand-receptor interactions may play the important roles in the development of GDM. Conclusion This study provided the first cell-type-specific transcriptomic alterations GDM placenta from single cell level, exploded the cell identities and cell-type-specific marker genes in the human placenta. In addition, it demonstrated the features of placental function and cell interactions for GDM.