  In 2009, the BESIII experiment has collected about 225M $\jpsi$ and 106M
$\psip$ samples, both of which are the world largest on-peak charmonium
production. Based on these dataset, BESIII has made great effort on the study
of the charmonium decays, some important of which have been reviewed in this
proceeding. In addition, a searching for new physics through the $CP/P$
violation process is reported.
