The development of bearing life-extension technologies requires in-depth understanding of the grease behavior in a bearing operation. In many cases, several difficulties commonly arise when attempting to observe the grease behavior directly from the bearing exterior without removing seals and shields while conducting conventional experiments. The work reported in this paper utilizes an X-ray computed tomography (CT) imaging system, one of the non-destructive detection tools, to capture the grease distribution in a ball bearing and grease internal flows, especially grease transition from churning to a channeling state. Additionally, numerical simulations of grease flows, Computational Fluid Dynamics for the macroscopic grease flows and Elastohydrodynamics for mesoscopic film thickness variation in the contact area, were respectively performed. An integrated multi-scale grease flow simulation scheme is targeted as the final goal of this work.