As a phenomenological description of the non-perturbative property of QCD, meson loop mechanism plays a crucial role in understanding some particular decay behaviors of heavy quarkonia. In this talk, I will present our estimations of meson loop contributions to some strong decay process, such as $\Upsilon(5S) \to \omega \chi_{bJ}$, $\psi(4160)/\psi(4040) \to \eta J/\psi$ and $\chi_{c1} \to VV$. In addition, the meson loop contributions to the radiative transition processes are also discussed.