Zirconia alloying is one of the most effective approaches used to obtain optimal performance of YTaO4 ceramics as thermal barrier coatings (TBCs), making it an important method for investigation. In this work, (ZrO2)x-(YTaO4)1-x (x = 0, 0.1, 0.2, 0.3) ceramics are synthesized via solid-state reaction, after which an analysis of the phase composition and microstructures of the samples is conducted using X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS) employed to characterize the variation of bond energy with composition reveals that Zr4+ ions simultaneously substitute Y3+ ions and Ta5+ ions in the structure of YTaO4 ceramics. Due to the zirconia alloying effect, the thermal conductivity of (ZrO2)x-(YTaO4)1-x ceramics significantly decreases, reaching a minimum of approximately 1.33 W m−1 K−1 at 900 °C, which is exceeding 40% lower than that of YSZ. The thermal expansion coefficients of (ZrO2)x-(YTaO4)1-x ceramics vary in some ranges (8.4–10.0 × 10−6 K−1, at 1200 °C), but are comparable to that of YSZ. In addition, this research systematically investigates the discipline of hardness and modulus changing with the composition. As is demonstrated by the excellent thermophysical properties it exhibits, (ZrO2)x-(YTaO4)1-x ceramic material is believed to be a prospective TBCs material.