Abstract: With the development of assisted reproductive technology and genetic analysis technology, the preimplantation genetic screening （PGS） is used to detect the numerical chromosomal abnormalities （aneuploid） in embryos, so as to improve pregnancy outcomes of in vitro fertilization-embryo transfer（IVF-ET）. New methods and technologies have been used in PGS, such as blastocyst stage biopsy, comparative genomic hybridization, microarrays and next generation sequencing, which increase the diagnose accuracy and decrease the risk of misdiagnosis. At the same time, PGS is also facing many challenges. The clinical application of PGS was reviewed in this article.

Key words: Preimplantation diagnosis, Reproductive techniques, assisted, Fertilization in vitro, Embryo transfer, Aneuploidy, Blastula, Nucleic acid hybridization, Microarray analysis, Sequence analysis, DNA, Chimera