The invention provides a kit, primers, probe sequences and a method for detecting fetus chromosome aneuploid. The kit comprises the multiple pairs of specific primers and a plurality of specific Taqman probes all of which are designed according to 13#, 18# and 21# chromogene sequences of the human, and further comprises a reaction system used for digital PCR, wherein the nucleotide sequence of the specific primers and the specific Taqman probes is SEQ ID NO: 1-90. The detection method comprises the steps that firstly, the specific primers and the specific Taqman probes are designed according to the 13#, 18# and 21# chromogene sequences of the human; secondly, peripheral blood of a (12-23)-week pregnant woman is collected for plasma DNA extracting; thirdly, the reaction system of the digital PCR amplification gene sequence is prepared; fourthly, the numbers of 13#, 18# and 21# chromosomes of a fetus are calculated through digital PCR detection for the number of the chromosomes, digital PCR is used for detecting FAM and VIC fluorescence of all reaction units of a chip, and the copy number of the 13# chromosome, the copy number of the 18# chromosome and the copy number of the 21# chromosome are calculated respectively. By means of the kit and the method, the number of the 13# chromosome, the number of the 18# chromosome and the number of the 21# chromosome of the fetus can be efficiently, quickly and accurately detected without invasion, and the kit and the method are beneficial to clinic application and popularization.