An electrically controllable radial birefringent pupil filter for modulation of transverse superresolution performance and axial extended focal depth is proposed. It consists of two parallel polarizers, an electro-optical crystal and a birefringent crystal with radial symmetry. The spatial modulation of the optical polarization state at the electro-optic crystal and the radial birefringent device is analyzed. The initial optical polarization state at the radial center is determined by the phase delay of the electro-optic crystal. Combined with the transverse polarization state modulation by the birefringent device, the control of the polarization state evolution path and the stage on the Poincaré sphere, and the redistribution of the optical intensity by spatially modulating the polarization state near the focus are realized. The control of transverse superresolution performance and the axial extended focal depth can be realized merely through the applied-voltage modulation, and the phase delay range can simultaeously be obtained.