OBJECTIVE：To eva luate content constituent characteristics and antiviral activity of main flavonnoids in genuine and non-genuine Scutellaria baicalensis ，and to investigate quality-efficiency relationship and effective substance. METHODS ： Totally 8 batches of S. baicalensis from different origins （S1-S8）were collected to prepare its water extract lyophilized powder. UPLC method was used to determine the contents of baicalin ，wogonoside，baicalein and wogonin ，and calculate their content constituent ratio. According to the content constituent ratio of flavonoids in S. baicalensis from different origins ，the mixture of the above four components was prepared as the corresponding simulated sample of flavonoids （E1-E8）. Using ribavirin as positive control，MTT assay and CPE method were used to investigate half toxic concentration （TD50）of the water extract from 8 batches of S. baicalensis and their corresponding simulated samples to human laryngeal carcinoma cell Hep-2 and their half inhibition concentration（IC50）to respiratory syncytial virus （RSV）；treatment indexes （TI）were calculated. Pearson correlation analysis for the content of baicalin ，wogonoside，baicalein and wogonin with their anti-RSV activity （IC50）was performed by SPSS 17.0 software. RESULTS ：The contents of baicalin and wogonoside in sample S 4（from Hebei Chengde ）were the highest ，and the contents of baicalein and wogonin in sample S 6（from Inner Mongolia- 2）were the highest. The contents of above 4 components were the lowest in sample S 6，S6，S7（from Beijing ），S4. The contents of flavonoid glycosides in sample S 4 were relatively higher， while those of corresponding glycosides were relatively lower ；the content constituent ratio of baicalin ， wogonoside，baicalein and wogonin was 1∶0.224∶0.111∶0.013. The contents of flavonoid glycosides in sample S6 wererelatively lower ，while those of glycosides were relatively 126.com higher；the content constituent ratio of above 4 components was 1∶0.241∶0.713∶0.106. TC 50 of S. bai calensis water extracts from different origins to Hep- 2 cells was all higher than 50 μg/mL， IC50 to RSV was 11.11-51.74 μg/mL；TI was 1.86-5.20. TC 50 of corresponding simulated samples of flavonoids was 23.11-52.23 μg/mL，while IC 50 to RSV was 4.87-14.61 μg/mL；TI was 1.85-4.75. The anti-RSV effects of water extract of S 4 from genuine origins（Hebei Chengde ）and its corresponding simulated sample E 4 were the strongest. Correlation analysis showed that the correlation coefficient between the contents of 4 flavonoids and antiviral activity was less than 0.5，and there was no significant correlation between them. CONCLUSIONS ：When the content constituent ratio of 4 main flavonoids in S. baicalensis was 1∶0.224∶ 0.111 ∶ 0.013，it has a strong inhibition effect on RSV. S. baicalensis from genuine origins has better constituent characteristics of flavonoids，which may be the important material basis for the best antiviral effect of genuine medicinal material.