Describe the genetic characteristics of Matrix protein coding region of HRSV isolates from Beijing and GenBank downloaded sequences.RT-PCR was performed to amplify the M protein gene of 2 A and 2 B subgroups HRSV isolates from Beijing in 2004. The RT-PCR products were sequenced for M protein coding region. The sequences of M protein coding region of 4 Beijing isolates and those downloaded from GenBank were compared and analyzed.The nucleotide acid and deduced amino acid different numbers between 2 A Beijing isolates and prototype strain Long were 24, 26 (3.1%, 3.4%) and 1 (0.39%). The nucleotide acid and deduced amino acid different numbers between 2 B Beijing 2004 isolates and reference strain 9320 were 16, 19 (2.1%, 2.46%) and 2, 1 (0.78%, 0.39%). The nucleotide acid and deduced amino acid different numbers were 24-119 (3.1%-15.4%) and 1-21 (0.39%-8.2%) respectively between 4 Beijing 2004 isolates and GenBank sequences.M gene was the highly preserved gene in the HRSV genome. However, numbers of variation occurred in the entire gene of M protein. The variation between A and B subgroups were widely distributed in the entire gene of M protein, while the differences within the A or B subgroups HRSV was pretty low. These sequence data will be the basic gene databank and will be contribute to the development of the quick gene diagnosis assay for HRSV.