With the development of a sustainable agriculture, especially in fruit production, researchers have known more and more effects of applied organic materials in eco-orchard on the increasing of ecosystem productivity, nutrient cycling, and ecosystem stability. Cover crops is one of the important conventional management measures in eco-orchards, and is widely believed to increase soil organic matter and soil fertility, conserve soil moisture, and increase habitat productivity, habitat complexity, and local biodiversity besides maintaining ecological equilibrium and improving fruit. And also many have reported positive relationships between intercropping in orchards and arthropod communities, but the details of the interactive effects of the aromatic plants used as intercrops on relationship of aphids and natural enemies are not well documented. During March 10 to September 30 in 2006 to 2007, we conducted a systematic survey about the population compositions, dynamics as well as time niche of aphids and their natural enemies under five treatments toward the pear trees that were all in 20-years old in full fruit production in pear plantation that is located of Daxing District in Beijing, China. Treatments were designed as the intercropping mint (Mentha haplocalyx B.), maidenhair (Tagetes patula L.) and basil (Ocimum basilicum L.), natural sward plots and clean tillage plot as control in pear orchard. The results showed that there were significant differences in aphids and natural enemies' population numbers, compositions, time series characteristics, time niche breadth and overlap among different intercropping treatments: (1) The temporal characters trend of three aphids (Aphanostigma jakusuiense Kishida, Aphis citricola van der Goot, Toxoptera piricola Matsunmra) and their natural enemies were similar to that in mint, maidenhair and basil intercropping plots, but the occurring numbers and time of the aphids and natural enemies were remarkably different from that in control. Compared with natural grass plot and clean tillage plot, the number of three aphids at intercropping aromatic plants plots decreased remarkably. All aphid peaks occurred at about 10d or earlier at intercropping aromatic plants plots than that in natural grass plot and clean tillage plot. (2) In all treatment regions, the time niche breadth index was small for aphids while it was large for its enemies. (3) All aphids except Aphis citricola, and predatory enemies had larger time niche breadth index in aromatic intercropping region than control; (4) The time niche overlap index varied significantly between aphids and natural enemies; (5) In all treatment regions, the correlation degree between different natural enemy groups and a certain specific aphid was similar, while it was different between a specific natural enemy and the three aphids among intercropping regions. We proved that changed quantity and constitution of aphid and its natural enemies, and decreased the group number of pest in the ecological environment of pear orchard. Moreover, intercropping aromatic plants can increase predator: prey ratio at 1∶1, and it is obviously larger than that in natural grass plot (1∶2.1) and clean tillage plot (1∶3.3). In conclusion, intercropping aromatic plants can efficiently depress group quantity of aphid, which is a preferred agricultural prevention and control method of aphid damage.