Fluids confined in nanochannel exhibit distinct phases and flow properties not shown in the bulk. These confined systems are involved in many industrial and engineering applications such as nanofluidic devices, biological membranes and therefore understanding and controlling the molecular behavior of confined liquids is important. Octamethylcyclotetrasiloxane (OMCTS) is a small macrocycle made of four covalently linked Si(Me)2O units which have been used as a model liquid in the experimental studies. However, much less is known about the mechanisms related to external stimuli such as shear and how those molecular behaviors in a confined system impact the flow properties of the whole liquid. In this study, we have investigated the structure and shear viscosity of OMCTS confined between two mica walls under shear, using molecular dynamics simulation. The results showed layering of OMCTS molecules, depending on the distance between two mica surfaces. In addition to this, the structural changes were observed accompanied by shear-thinning behavior when we applied shear to the system.