The invention discloses a mutational COL4A5 gene and application thereof, in particular to a method for the detection of Alport syndrome mutations of the COL4A5 gene. The encoded IV-type collagen alpha 5 serine on 1371 site is mutated into a terminator under action of mutation of the COL4A5 gene and truncated IV-type collagen alpha 5 chain is caused. The mutational COL4A5 genes or the mutational IV-type collagen alpha 5 chain is used in the preparation of an AS detection agent or a detection device. The detection device preferably comprises a detection platform including a gene chip containing a COL4A5 gene for detecting mutations. The mutational COL4A5 gene provides the pathogenic loci of AS novel pathogenic genes, and provides a new molecular biological basis for the diagnosis of the disease.