Provided is a dielectric resonator, comprising a dielectric body formed from a dielectric and a conductive layer covering the dielectric body; the dielectric body comprises a first blind hole extending from the conductive layer to the interior of the dielectric body and being used to change the resonance frequency of the dielectric resonator, the inner wall of the first blind hole being a dielectric. The present invention achieves regulation of the frequency of a dielectric resonator by providing a first blind hole in a dielectric body and changing the cross sectional area and depth of the first blind hole. Also provided are a dielectric filter and a communication device.