Change rule of dielectric properties on environment temperature for microarc oxidation (MAO) coatings on Zr alloy was investigated, and their dielectric frequency spectra in range of ?100~250 ℃ were understood. A bipolar MAO pulse power supply in constant voltage mode is used to conduct MAO treatment on Zr-0.39Sn-0.32Nb alloy in silicate electrolyte. The morphologies and phase compositions of MAO ceramic coatings were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and laser Raman spectrum. A variable-temperature dielectric spectrometer was used to measure the dielectric constant, dielectric loss, and the frequency spectrum (0.01 Hz~1 MHz) of the micro-arc oxide coatings with different thicknesses in the range of ?100~250 ℃ The 20~45 μm thickness micro-arc oxidation ceramic coatings prepared on the surface of Zr-0.39Sn-0.32Nb alloy consisted of monoclinic zirconia (m-ZrO2) and a little tetragonal zirconia (t-ZrO2). The compact inner layer of MAO coatings played a key role on their dielectric property, and the porous outer layer reduced their insulating property. In the temperature range of ?100~250 ℃, the dielectric constant, dielectric loss and conductivity of MAO coatings increased rapidly with the increase of temperature in low frequency zone, but the temperature hardly affected their dielectric property in high frequency zone. Meanwhile, the dielectric property of MAO coatings of Zr alloy at 0~100 ℃ kept stable. Their conductivity was about 10?12 S/m at 50 Hz and 20 ℃. Hence, the environment temperature had a great influence on dielectric property of MAO ceramic coatings on Zr alloys, especially in low frequency zone.