Wheat is the most widely cultivated crop in the world. Yet, its yield and quality are severely affected by fungal and insect pests. Among the insect pests of wheat, cereal aphids frequently cause significant damage. The species of aphids commonly infesting cereals in China are the grain aphids, Sitobion avenae, Sitobion graminum and Rhopalosiphum padi. They can substantially reduce cereal yield and quality because of their capacity for extremely rapid population growth. Moreover, injury by those cereal aphids is both direct, through injection of chemical substances in saliva and mechanical damage, as well as indirect, through the effect of honeydew and pathogenic fungi. In addition, they are all a vector of barley yellow dwarf virus. However, the three species of wheat aphids have different feeding sites and virus transmission ability. The objective of the study was to study the potential machanism of separation in ecologic niche and virus transmission ability by analysing the feeding behaviors of three species aphids. Their feeding behaviors on one wheat variety (ZhengMai 9023) were comparatively tested using electrical penetration graph (EPG) and an image analysis system. The EPG technique was used because it provides continuous information on feeding/probing events. The main results are shown as follows: (1) The xylem ingestion (waveform G) of R. padi occurred earliest (98.11±27.26min) among the three species of wheat aphids (P<0.05), and both total duration of waveform G (94.37±22.42min) along with its average duration per probe (45.62±18.82)min were all significantly longer than those of S. avenae and S. graminum (P<0.05). Total duration of salivation into sieve elements (waveform E1) and its duration per probe of S. avenae ((33.23±6.17)min and (7.62±1.72)min, respectively) were all the longest among the three aphid species (P<0.05). However, the total duration of phloem ingestion (waveform E2) of S. graminum (159.71±13.53)min and its duration per probe (84.32±16.85)min were significantly longer than those of the other two aphid species (P<0.05). The results demonstrated that each of three aphid species has different feeding strategies. R. padi needs more water and inorganic salt than the other two species since it spends more time during xylem ingestion. S. avenae maybe increases food utilization by secreting more saliva, while S. graminum gains enough food by increasing phloem feeding time. (2) Waveform pd is related to a short intracellular puncture during the pathway, and it can be separated into three sub-patterns, pdⅠ, pdⅡ and pdⅢ. Sub-phases of pdⅡ were considered in connection with transmitting and obtaining the virus. The number of pd waveforms during 5h of EPG recording for S. avenae, S. graminum and R. padi were 44.73±4.52, 51.97±7.82 and 32.99±4.22, respectively. The mean time per pdⅡ-2 and pdⅡ-3 waveform of S. graminum were the longest ((2.27±0.14)sec and (2.36±0.12)sec, respectively) among the three species. Hence, the probability of virus transmission and acquisition of S. graminum was the highest, which may be the main reason why S. graminum is the strongest virus vector among these three aphid species.