Objective　The　objective　of　the　study　is　to　investigate　biofilm　forming　ability,　distribution　of　biofilm　associated　genes　of　the　clinically　isolated　bovine　mastitis　Staphylococcus　and　the　correlation　of　them.　Methods　Silver　staining,　SEM　and　crystal　violet　staining　were　conducted　for　the　detection　of　biofilm　forming　ability　in　24-well　plates.　Genes　of　bap,　icaAD,　icaBC,　sar,　agr,　sigB,　clfaA,　clfaB,　fnbpA　and　fnbpB　were　amplified　by　PCR.　Results　Formation　of　biofilm　could　be　found　macroscopically　in　120　out　of　137　strains　by　silver　stainning,　the　biofilm　formation　rate　of　87.6%.　It　showed　that　5　strains　didn＇t　adhere　to　the　surface　of　silica　gel　by　crystal　violet　staining,　while　the　rest　132　ones　did.　Bap　was　amplified　in　57　isolates　and　icaAD　and　icaBC　in　43　and　54　strains　respectively;　sigB,　sar　and　agr　are　amplified　in　73,　49　and　38　isolates,　and　clfaA　and　clfaB　in　76　and　50　strains　respectively;　fnbpA　was　present　in　52　strains　and　fnbpB　in　26　isolates.　Conclusion　It　revealed　that　bap,　sigB,　sar,　icaAD　and　icaBC　may　be　crucial　biofilm　associated　genes,　for　these　genes　are　present　more　in　biofilm-positive　strains　than　in　biofilm-negative　strains.　There　is　no　obvious　difference　between　the　frequency　of　agr　in　biofilm-positive　strains　and　that　in　biofilm-negative　strains,　which　may　because　the　role　of　agr　in　biofilm　developmemt　is　still　in　controversial.　The　distribution　of　clfaA,　clfaB,　fnbpA　and　fnbpB　in　biofilm-positive　strains　is　not　greatly　different　from　that　in　biofilm-negative　strains,　however,　the　distribution　of　these　genes　in　a　few　of　isolates　suggests　that　these　genes　are　positive　for　biofilm　formation.