Objective：To study and analyze the differences in microbial diversity and species differences of vaginal flora caused by recurrent spontaneous abortion，and to preliminarily explain the role of vaginal microecology in the development of recurrent sponta－neous abortion. Methods：21 patients with recurrent spontaneous abortion admitted to our hospital from January 2010 to December 2016 and 20 cases of induced abortion to normal pregnancy were selected as subjects in this study. There was no significant difference in pregnancy time between the two groups（P>0.05），and various data for clinical diagnosis and treatment were collected at the same time. After the routine collection of medical history，vaginal secretions were collected. Metagenomic sequencing was used to analyze microbial types and microbial genomic data of the secretions，so as to clarify differences and functionality. Results：Clinical data showed that the incidence of vaginal inflammation in patients with recurrent spontaneous abortion was higher than that in normal pregnancy. The vaginal microbial diversity of patients with recurrent spontaneous abortion was significantly higher than that of normal pregnancy，and the microbial gene abundance was lower than that of normal pregnancy. Through differential species identification analysis，hundreds of different differential microorganisms were selected，and 16 different micro-organisms were selected according to statistical requirements and the actual conditions of the sam－ples. Five of the strains were not found in the vagina of normal pregnant people，but clearly present in the vagina of patients with recurrent spontaneous abortion and had a high abun－dance；8 strains were present in the vagina of normal pregnant people and had a high abundance，but were not detected in the vagina of patients with recurrent spontaneous abortion；the other three strains had large differences in abundance. The functional en－richment analysis of these differential microorganisms showed that there are statistical differences in molecular function，biological processes and cell composition among them，which were reflected in metabolic processes such as amino acid metabolism，glucose metabolism，energy metabolism，nucleotide metabolism and lipid metabolism，and various amino acid metabolism and energy metabolism in particular. In addition，we also found that the influence of metabolic dysfunction can also cause abnormal vaginal in－ternal cell signal transduction，endocrine and metabolic disease，causing cardiovascular disease in endocrine and metabolic diseases in return. Conclusion：The low immunity of patients with recurrent spontaneous abortion may be associated with vaginal inflammation caused by vaginal microecological disorders. In addition to the exchange of different types of lactic acid bacteria，new strains such as Gardnerella and Plasmodium may also play an important role in the occurrence and development of recurrent spontaneous abortion.