[Aim]  To evaluate the potential of the predatory bug Orius sauteri (Hemiptera: Anthocoridae) to act as a biocontrol agent for the economically important bird cherry-oat aphid Rhopalosiphum padi (Hemiptera: Aphididae). [Methods]  Under controlled laboratory conditions, this study systematically evaluated the functional response and searching efficiency of O. sauteri preying on adults of R. padi, and further explored the effects of intraspecific interference on its predation efficiency under different natural enemy densities. [Results]  Predatory functional responses of both 5th instar nymphs and adults fitted both the Holling II and Holling III equations. In the Holling II model, the attack efficiencies of 5th instar nymphs, and female and male adults were 0.764, 0.802, and 0.754, respectively, and their respective predation capacities were 11.274, 18.670, and 10.196. Adult females were the most efficient predators of R. padi. In the Holling III model, 5th instar nymphs, and female and male adults had a daily maximum consumption of 11.250, 16.030, and 10.620 individuals, respectively, and an optimal search density of 7.326, 9.386, and 7.258 individuals per dish, respectively. Search efficiency was negatively correlated with predator density, and average individual predation capacity was negatively correlated with the density of O. sauteri. [Conclusion]  These results suggest that O. sauteri could be an effective biological control for R. padi.