Abstract: Avian infectious bronchitis virus strains that prevailed in 1992-2005 in Shandong Province were collected. The spike protein （S1） gene，matrix （M） protein gene and nucleocapsid （N） gene of these virus were cloned and sequenced. The sequences of S1 gene，M gene and N gene published in GenBank were also collected. The homologies and correlations in nucleotide and amino acid of S1 gene，M gene and N gene were compared and analyzed by DNAStar and SPSS 8.0 software. The results showed the correlation coefficient of nucleotide genetic variation between S1 gene and M gene，S1 gene and N gene，M gene and N gene was 0.483，0.570 and 0.620，respectively，which indicated that the genetic variation among S1，M and N genes showed not only synchronism but also independence. The phylogenetic trees based on amino acid sequences of S1 and N genes from 9 Shandong IBV and 17 reference strains indicated that strains of Shandong IBV isolated during 10 years showed close genetic relationship，and the phylogenetic trees based on amino acid sequences of M gene showed that only 3 Shandong IBV had certain relationship. Thus，it was indicated that gene recombination had been observed in IBV.

Key words: avian infectious bronchitis virus, S1 gene, N gene, M gene, nucleotide homology, heredity mutation, correlation