At present the world's largest sample of 1.3 billion J/psi decay has been collected by the BESIII detector, which provides a unique opportunity to investigate light meson decays. The $\eta$ and $\eta\prime$ hadronic decays are sensitive tools for the investigations of $\pi$-$\pi$ and $\eta$-$\pi$ interactions, symmetry breaking, and for testing the Chiral Perturbation Theory. In this article, BESIII presents new results on amplitude analyses of the Dalitz decays $\eta\prime\to 3\pi$, $\eta\prime\to\eta\pi\pi$, $\eta\prime\to\gamma\pi\pi$ and $\eta\prime\to\gamma\gamma\pi^{0}$, on the observation of new decay modes and on searches for rare or forbidden decays. The $a_{0}(980)$-$f_{0}(980)$ mixing is an important probe to the nature of these two light scalars. The first observation of $a_{0}(980)$-$f_{0}(980)$ mixing will be presented.