One of the aims of researchers study is always to improve the quality and strength of materials which use in reinforced concrete (RC) members. Steel rebars are one of the most widely used materials in structural members which the quality has an important role in structure performance. The performance of high strength rebars has been compared to conventional reinforcements In studies which have been conducted on the use of this type of rebars in columns and beam-column connections. But due to the effect of improving quality and the yield stress of rebars,which are not completely known for researchers, thus this study tries to find out the effect of using high strength reinforcements on the behavior of RC columns. One of the advantages of using high strength reinforcement is to reduce the amount of longitudinal rebars. If the structural performance of high strength steel (A-IV) would be appropriate, The amount of longitudinal reinforcement of column can be reduced to about 30% without any changes in the load-carrying capacity and structural behavior. In this study, the performance of rebars with yield stress of 600 MPa (A-IV) and rebars with the yield stress of 420 MPa (A-III) have been investigated. This study was conducted in two experimental parts. In the first part, 20 RC columns with 500 mm height and 133×133 mm cross, were tested under axial load with eccentricity of zero, 60 and 90 mm and under 4-point flexural bending test to investigate the axial and flexural behavior of columns. Half of the columns are reinforced with high strength longitudinal rebars (A-IV) and the other half columns are reinforced with conventional longitudinal rebars (A-III).The specimens are designed in a way to have the same flexural capacity , so that the product of is similar for both categories of columns. In the second part, 2 beam-column connections with cale were tested under lateral cyclic quasi-static load. these two beam-column connections are designed to have the same flexural capacity. So that the moment capacity of beam and column of connection which is reinforced with conventional rebars (A-III) is similar to the one which is reinforced with high strength rebars (A-IV) The experimental results in the first part of this study demonstrated that although the amount of longitudinal rebars was reduced to about 30% in columns with high strength rebars (A-IV), but load carrying capacity did not noticeably change in comparison with reference specimens. The ductility index before the balanced point (eccentricity of zero and 60 mm) decreased in columns reinforced with high strength rebar in comparison with reference specimens .So while the eccentricity increases, the ductility index difference reduces. In the second part , the results showed that the performance of high strength rebars (A-IV) is similar to specimen which reinforced with A-III rebars up to drift ratio of 4% and the behavior of the beam-column connection which reinforced with high strength rebar is desirable up to this lateral displacement in terms of load capacity, dumping ratio and energy dissipation. Key Words High strength rebar, Concrete reinforced column, High strength concrete, Beam-column connection, Eccentric loading, Lateral cyclic loading.