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, som
e important of which have been reviewed in this proceeding. In addition, a searching for new physics through the $CP/P$ violation process is reported.
