This study presents a comprehensive transcriptional map of human preimplantation development, including the transcriptomes of 1,529 individual cells from 88 human embryos. The data reveal the concurrent establishment of trophectoderm, epiblast, and primitive endoderm lineages, coinciding with blastocyst formation. Female cells in all three lineages achieve dosage compensation of X chromosome RNA levels prior to implantation, with XIST transcription from both alleles throughout the process. The study also identifies novel lineage-specific genes and subpopulations within the trophoblast lineage. Additionally, it demonstrates that X chromosome dosage compensation in human preimplantation embryos involves the gradual downregulation of both X chromosomes, rather than the complete silencing of one chromosome as occurs in mice. The findings provide valuable insights into early human development and have broad utility in future studies on human development and stem cell research.This study presents a comprehensive transcriptional map of human preimplantation development, including the transcriptomes of 1,529 individual cells from 88 human embryos. The data reveal the concurrent establishment of trophectoderm, epiblast, and primitive endoderm lineages, coinciding with blastocyst formation. Female cells in all three lineages achieve dosage compensation of X chromosome RNA levels prior to implantation, with XIST transcription from both alleles throughout the process. The study also identifies novel lineage-specific genes and subpopulations within the trophoblast lineage. Additionally, it demonstrates that X chromosome dosage compensation in human preimplantation embryos involves the gradual downregulation of both X chromosomes, rather than the complete silencing of one chromosome as occurs in mice. The findings provide valuable insights into early human development and have broad utility in future studies on human development and stem cell research.