The invention discloses a low-frequency low-dielectric-loss Ag and Ta co-doped titanium dioxide-based dielectric ceramic material and a preparation method thereof. The general formula of the ceramic material is (Ag<1/4>Ta<3/4>)Ti<1-x>O<2>, wherein x represents a mole fraction, and the x value is selected from 0.005 to 0.01. According to the invention, the preparation method of the ceramic material is simple, good in repeatability and high in finished-product ratio; through introduction of a metal element Ag in a Ta singly-doped titanium dioxide-based ceramic material, the ceramic material has a high dielectric constant (>104) and a low dielectric loss (<0.14) within the frequency range of 40-106Hz, especially the low-frequency dielectric loss of the ceramic material is significantly reduced, and the dielectric loss is always kept at 0.07 or less in the frequency range of 40-103Hz; the ceramic material has excellent frequency and temperature stability, and the temperature stability is kept at a range from -15% to 15% and meets parameter requirements of a ceramic capacitor; and the Ag and Ta co-doped titanium dioxide-based dielectric ceramic material has great application value.