Abstract: Preimplantation genetic diagnosis /preimplantation genetic screening（PGD/PGS） is a low-risk technique of early preimplantation detection developed in recent 20 years. It needs to do firstly the biopsy oocyte or preimplantation embryo，then to analyze genetic information by molecular biological technique. At last, those normal embryos were chosen for transplantation. PGD/PGS can avoid the pregnancies of those genetically sick babies，improve the pregnancy rate and the live-birth rate，and can reduce the miscarriage rate and the multiple-gestation rate. This technique is mainly used for the elderly，recurrent miscarriage，repeated implantation failure patients and the couples with high-risk genetic diseases. We summarized those methods used in PGD/PGS, including FISH，PCR，CGH，array-CGH，array-SNP and high-throughput sequencing. All kinds of methods have their own application fields, merits and shortcomings. The single-celled high-throughput sequencing technology shows its obvious advantage in high sensitivity，accuracy and flexibility，which should become a powerful detection means in PGD/PGS with its further development and maturation.

Key words: Preimplantation diagnosis, Genetic screening, Fertilization in vitro, Embryo transfer, Aneuploidy