Abstract: In this study, the stylet penetration behaviours of Sitobion avenae F. and Rhopalosiphum padi L. on wheat cultivars with different degrees of resistance were recorded with EPG (Electrical Penetration Graph) technique. Results showed the specific wave patterns of aphid penetration on the four tested cultivars (Hongmanghong, Xiaobaidongmei, kok-1679 and L₁) were almost similar, but there were differences in thestart time, repeats and duration. The time for the first appearance of E₁ [N] and the rate of total duration of E₂ to total recording time (E₂ %) could be taken as the main physiological parameters aeeociated with the cultivars resistance. Based on the major wavepatterns' parameters, the cluster analysis was used to distigush resistant levels of the tested cultivars and the result was fit basically with the life table parameters in lab and the evaluation in field. In the end of this article, the possible location of the resistant factors, function in resisatant evaluation by EPG and factors affecting EPG recording were discussed briefly.