The quantum confined energy levels in Ge quantum dots and the coulomb charging energy per added hole can be derived by deep level transient spectroscopy (DLTS). The number of holes captured by quantum dots call be controlled by varying the width of applied pulse voltage in the DLTS measurement. The Coulomb charging energy per added hole can be deduced from the energy step of the activation energy in the filling time dependent deep level transient spectra. The experiment results are confirmed by computer simulation.