Three stilbenoids with high influenza neuraminidase (NA) inhibition were discovered through high throughput screening.In order to primarily study their structure-activity relationship (SAR), eight stilbenoids were examined on the inhibitory effects of NAs which were from three different subtypes of influenza virus strains, and their in vitro anti-viral activities were also assessed using influenza virus induced cytopathic effect (CPE) reduction method, three of them, namely gnetupendin B (1), isorhapontigenin (2) and broresol A (3) displayed significant in vitro anti-influenza viral activities with IC50 values of 16.23, 16.58 and 14.45 →mol·L-1 , respectively.The results indicated that 3-OH and 5-OH are essential functionalities to their activities, and hydrophobic groups at C2 and C3 positions can increase their activities.These findings will provide important information for new drug design and for the utilization and exploitation of stilbenoids for influenza treatment and prevention.