Abstract: Studies on the occurrence and dispersion of Orius sauteri in relation to ground cover vegetation in apple orchard and adjacent farms were carried out in Beijing during 1992~1995. Results showed that O. sauteri overwintered as female adults on weeds such as Lagopsis supina and Hemistepta lyrata and continued to prey on aphids on these plants in early season. When L. supina gradually dried up in June, O. sauteri began to move to alfalfa and built up quickly, then dispersed to apple trees. As aphids and mites populations soon decreased rapidly on these plants in the orchard, O. sauteri adults migrated to adjacent vegetable and corn fields in late June. At the end of September they returned to apple orchard and overwintered on L. supina and H. lyrata. It is pointed out that diversity of ground cover vegetation in the apple orchard is favorable to the augmentation of O. sauteri and hence increase the efficacy of biological control of insect pests.