Provided are a method and a device for detecting a genetic mutation, and a kit for typing genotypes of a pregnant woman and a fetus. The method comprises: performing high-throughput sequencing on free DNA in a pregnant woman's peripheral blood to obtain sequencing data; comparing the sequencing data with reference genome to obtain SNP sites; performing mixed genotyping on each SNP site to obtain target genotypes for each SNP site; and selecting a mutation site that causes the gene mutation from the genotype of the fetus in the target genotypes.