From subcellular to tissue scale, plant cells maintain a distinctive hierarchy in its structural organization. However, due to microscale size and the lack of knowledge of the mechanics of plant cell and how they adhere to each other, the bridging between subcellular and extracellular scale is yet to be understood sufficiently. In this study, we have taken an onion outer epidermal peel, which is an array of one side wall profile from many cells, as the representative of a plant tissue and developed a framework of structure-based multiscale finite element method (FEM) computational model to scale-up mechanical properties from subcellular to tissue scale. A 3D repetitive volume element (RVE), which includes both subcellular and extracellular parameters, was built with ABAQUS® (a finite element software). Two dimensionally arranged RVEs would make a tissue patch of multiple cells. A sensitivity analysis was performed to understand the contribution of intercellular interaction or middle lamella (ML) to overall mechanical responses. We found that a ML layer, which was stiffer than wall fragment, did not have a major contribution to tissue scale mechanical properties. Once validated with experimental results at the same scale and environmental condition, this model will be used as a framework to study the contribution of extracellular parameters to overall mechanical responses in a variety of model system manifesting multiscale characteristics.