Neutron scattering directly measures the fluctuation of nucleus positions and has been widely used to probe atomic motions in various soft-matter materials. Here, we combined the neutron scattering, deuteration technique and molecular dynamics simulation to reveal the dynamics of protein and its surface water, and explore the physical mechanism underneath several important biophysical phenomena: protein dynamical transition, sub-diffusion of bio hydration water, and the competition between entropy and enthalpy during protein unfolding.