New results of the investigation of shielded dielectric ball resonator (DBR) with whispering gallery modes (WGM's) are represented The characteristic relations TM and TE modes are obtained. The dependence of resonant frequencies and Q-factor of WGM's on resonator parameters have been calculated numerically. It is shown that the shielding of DBR provides the increasing modes Q-factor in ten times. A good agreement between theoretical and experimental results are obtained.