A bacterium was isolated from rice seeds in Jiaxing of Zhejiang Province, China. It has been confirmed as Acidovorax avenae subsp. avenae by bacteriological tests, differential media, pathogenicity test, Biologand fatty acid methyl ester(FAME) analysis(computer aided numeric taxonomic methods). It revealed that A. avenae subsp. avenae is different from the bacterium recorded in Zhejiang in 1960s although they produced similar symptom, bacterial stripe, on rice seedlings. A. avenae subsp. avenae could be isolated from discolored seeds aswell as from healthy looking seeds of rice. They significantly affected seed germination and seed vigor when 1010cfu/mL and 108 cfu/mL of the bacterium were inoculated on rice seeds. The bacterium could transmitted from seeds to seedlings with 0.2%-5.0% of infection. This suggested that rice seed is very infectant infection source fort ransmission of bacterial stripe and care must be taken for introduction of seeds.