The present invention discloses an apparatus for detecting gene mutation, and a kit for typing the genotype of pregnant women and fetuses. The apparatus comprises a detection module, a comparison module, a target mixing genotype determination module and a mutation site screening module, wherein the different SNP loci between maternal and fetal genomic information and a reference genome can be obtained through the detection module and the comparison module, and the mixing genotype of the pseudotetraploid comprising the pregnant woman and the fetus is typed by using the target mixing genotype determination module to obtain the maternal and fetal genotypes at each SNP locus, such that all possible genetic mutations of the fetus can be detected by using only the peripheral blood sample of thepregnant woman; and with the apparatus, the separate sequencing of the sample from the father source or the mother source is not required, and all possible genetic mutations of the fetus can be detected by only using the peripheral blood sample sequencing data of the pregnant woman, such that the convenient and diversified services are provided for the fetal gene detection.