Colossal permittivity (CP) materials show an attractive potential application in field of integrating circuit and medical equipment owing to ultrahigh permittivity. Herein, a good CP performance (ɛ>104, tan δ < 0.1, 1 kHz) and insulation performance (Eb > 2 kV/cm) have been realized in (Zn1/2W1/2)x (Zn1/3Nb2/3)0.01-xTi0.99O2 ceramics (ZWNTOx) at x = 0.25 %. Both the electrons pinned defect dipoles (EPDD) and internal barrier layer capacitance (IBLC) effect can be considered as the CP mechanism of ZWNTOx ceramics. Besides, the overall resistance is improved as increasing x contents are accompanied by decreasing of oxygen vacancies concentration in ceramics, which should be excited by formation of Zn2+-W6+ ion pairs. At same time, the point defects induced by Zn2+, Nb5+ ions ensure a high permittivity and a low dielectric loss of ZWNTOx ceramics. The co-existence of multiple defective structures has been exploited to jointly optimize dielectric performance and insulation performance in ceramics.