Due to the high production rate of light mesons in $J/\psi$ decays, the hight statistics sample of $1.3$ billion of $J/\psi$ events provides an ideal laboratory to investigate the decay dynamics of light mesons, in particular for $\eta$ and $\eta'$ mesons. Recently, the BESIII experiment made significant progresses in $\eta$ and $\eta'$ decays, including their hadronic and rare decays investigation, which will be discussed in this proceeding.