A synchrotron radiation experiment and a large-scale simulation are indispensable for development new functional rubber materials in recent years. In this series of lectures, I will try to explain about an analysis of structure of filled rubber vulcanizates by cooperation of a synchrotron radiation experiment and a large-scale simulation. In this fourth article, I will discuss coarse-grained molecular dynamics (CGMD) simulations of hydrogenated styrene butadiene rubber (SBR) which shows very high strength. Since the high strength of hydrogenated SBR is thought to be due to the increment of entanglement density with hydrogenation, we have added angle potential to Kremer-Grest model in order to control entanglement density. We conducted CGMD simulations of hydrogenated SBR with this model. The stress-strain curves and the tan ƒÂ master curves by simulation reproduced experimental data. Then we conclude that the increment of entanglement density plays an important roll in mechanical properties of hydrogenated SBR.