Active ingredients of 20 traditional Chinese medicines were extracted by ethanol circumfluence,water decoction,and ultrasonic extraction.Double dilution method is used to determine the antibacterial activity on Pasteurella multocida in vitro.And then the joint bacteriostatic activities of a few traditional Chinese medicines were evaluated.The result showed that the minimal inhibitory concentration (MIC) was in a range of 6.25~50 mg/mL mugwort leaf (Artemisia argyi),Rhizoma coptidis,Cortex phellodendri,Cortex fraxini,Garden burnet,Giant knotweed’s extracts,in range of 50 to 100 mg/mL for Radix paeoniaerubra,Radix-polygonimultiflori,Herba artemisiae capillaris,Rhizomabelamcandae,Licorice root,Dandelion,Cortex dictamni’s extracts,and more than 100 mg/mL for Honeysuckle，Radix bupleuri，Radix isatidis，Prunella vulgaris，Herba andrographitis，Rhizoma anemarrhenae，Radix sophorae flavescentis’s extracts.The results of joint bacteriostatic test showed that the fractional inhibitory concentration index (FICI) of R.coptidis,C.phellodendri,C.fraxini,G.knotweed,and A.argyi were less than or equal to 0.5 and the fractional inhibitory concentration index (FICI) of C.phellodendri,C.fraxini,R.coptidis and G.knotweed,Qin leather,G.burnet and C.phellodendri were more than or equal to 2.In conclusion,R.coptidis,C.phellodendri,G.burnet,and A.argyi had good antimicrobial activities against P.multocida. R.coptidis,C.phellodendri,G.burnet and Mugwort showed additive or synergy action,while Sanguisorba and C.phellodendri showed antagonistic action.