The mechanical properties of polymers are strongly influenced by meso-scale (10-9~10-3 m) structure such as entanglement, molecular weight distribution, orientation, etc. It is important to understand the relationship between the mechanical properties of polymeric material and meso-scale structure. Some studies related to the relationship have been made. However detail of the relationship is still unclear. Especially, the studies emphasize on entanglement and branch are few. This study aims to clear the role of entanglement and branch for mechanical properties by simulating the meso-scale structure using 3D network models. In the models, there are two structures considered. One of them has no branch, and, others have branch. Large strain deformation of network models is evolved via improved molecular dynamics analysis.