The invention relates to a superwide-temperature low-loss lead-free ceramic capacitor dielectric material, belonging to the technical field of electronic information materials. The chemical formula is (1-x)[0.94(0.75Bi[1/2]Na[1/2]TiO[3]-0.25NaNbO[3])-0.06BaTiO[3])]-xCaZrO[3], wherein 0.10<=x<0.15. The preparation method comprises the following steps: weighing Bi2O3, Na2CO3, BaCO3, TiO2, Nb2O5, CaO and ZrO2 according to the mole ratio of metal elements as initial raw materials; after carrying out primary ball milling, carrying out presintering; and grinding the presintered powder, carrying out ball milling, drying, grinding into powder, granulating by using a polyvinyl alcohol water solution as an adhesive, carrying out pressure molding, discharging the batch, carrying out high-temperature sintering, and carrying out furnace cooling. The dielectric material can maintain excellent capacitance temperature stability within a superwide temperature range, and the dielectric loss is lower than 3% in the whole temperature range.