Wheat is the main diet of the world population and an economically strategic product in Iran. Among the wheat pests, aphids are the most important groups and sometimes key pests of wheat causing direct damage by feeding on sap of phloem vessel and also indirect damage through transmitting plant pathogens. Therefore, the study of biodiversity and structure of these insect species in agro-ecosystems such as fields can be very helpful in their better management. Community structure of aphids was studied in a wheat field in Saman Region (E= 50° 88′, N= 23 ͦ 25ʹ), Chaharmahal and Bakhtiari Province during 2017. In order to sample the assemblage of wheat aphids, 100 wheat plants were randomly selected and then all aphids on each plant were removed by a fine brush and sometimes by beating the whole wheat plants on a white tray. This sampling procedure was repeated five times by an interval of two weeks. The collected specimens were then preserved in Eppendorf tubes (2 ml) containing 75% alcohol. They were then mounted on microscopic slides and identified based on morphological characters. Maczey's procedure and non-parametric estimators Contains Chao-Quantitative, Chao Presence-Absence, 1st and 2nd order Jackknife were used to determine the dominance level of each species and to estimate the maximum of species richness of aphid in the studied wheat field, respectively. The diversity of aphids along the sampling period was compared by Renyi's diversity ordering method. The data was statistically analyzed using SDR4 software. Results showed that eight wheat aphid species were collected and identified. The most abundant species were the Russian Wheat Aphid, Diuraphis noxia (Mordvilko, 1913) and the rose-grass aphid, Metopolophium dirhodum (Walker, 1849), with 53.05 and 43.47 percent of the total aphid individuals, respectively and determined as eudominant species. Rhopalosiphum padi (L., 1758) and Sitobion avenae (F., 1775) were determined as recedent. Sipha elegans (Del Guercio, 1905), Forda hirsuta (Mordvilko, 1928), Sipha sp. and Rhopalosiphum sp. were determined as subrecedent. Non-parametric methods of estimating species richness showed that additional sampling would yield at most 12 wheat aphid species in wheat fields. Diversity ordering using Renyi's showed that the species diversity of aphids in wheat fields of Saman region was at the highest order in the sampling date 2017.5.5 and the two sampling dates, 2017.6.5 and 2017.04.5, were the following orders, respectively.