In order to research the sintering mechanism of Y2O3 on CaZrO3, CaZrO3 was synthesized by solid reaction using analytical ZrO2 and CaCO3 as raw materials and Y2O3 as additive. The liner change rate, the relative density, XRD and the microstructure of the CaZrO3 samples were determined, and the effect of Y2O3 on sintering of CaZrO3 was researched. The results show that the sintering property of CaZrO3 is enhanced by adding Y2O3. When the content of Y2O3 is lower than 2 % (mass-%), the lattice volume of CaZrO3 increases to 0.262 nm3, which is attributed to Zr4+ being replaced by Y3+ in the CaZrO3 crystal. However, the content of Y2O3 is up to 4 %, and the lattice volume decreases due to Ca2+ being replaced by Y3+. The liner change rate of the samples increases with increasing Y2O3 additive. When Y2O3 is 4 %, the liner change rate of CaZrO3 reaches maximum (26.9 %). The relative density of the samples increases from 63.99 to 84.45 % with increasing addition of Y2O3, and the average grain size of CaZrO3 increases from 1.64 to 2.65 μm when the additive increases from 0 to 4 %.