  Recent results from BES and CLEOc experiments on charmonium decays using
J/psi, psi' and psi'' data samples collected in e+e- annihilation are reviewed,
including the measurement of the relative phase between strong and
electromagnetic decays of psi', the study of the ``rho pi puzzle'' in J/psi and
psi' decays, and the search for the non-DDbar decays of psi''. The decays of
chi_cJ produced in psi' radiative transition are also reviewed. These new
results shed light on the understanding of QCD.
