Connections are one of the most important members of the building, which, after the Northrich earthquakes in 1994 and Kobe in 1995, attracted the attention of engineers and caused changes in design and implementation. Composite connection of steel beam to concrete column (RCS) was investigated due to reduction of formatting concrete, stability versus of seismic and high ductility. In this paper, the connection of steel beam to concrete column (RCS) was investigated, and the effect of loading patterns and also the height of the covering plate around the concrete column was evaluated in ABAQUS finite element software. The results of the analysis showed that the loading patterns of SAC and FEMA-461 increased the final lateral load and bending moment and decrease in the height of the covering plate around the concrete column was effective on the connection behavior, so that the reduction it caused arise final lateral load and bending moment and decreased the stress and strain.