Objective To observe the effect of rabbit sacculus rotundus peptides on virulent Newcastle disease virus (NDV). Methods Virulent NDV was treated with rabbit sacculus rotundus peptides, and inoculated into chicken embryo. The erythrocyte agglutination titer of virulent NDV in chicken embryo allantoic fluids was measured, and pathological changes of chicken embryo were examined. Results The erythrocyte agglutination titer of virulent NDV was lower than that of control series, and the pathological changes were less serious than those in control series, indicating that rabbit sacculus rotundus peptides could inhibit the pathological changes of chicken embryo caused by virulent NDV. Conclusion The rabbit sacculus rotundus peptides has inhibitory effect on virulent NDV in vitro.