The effect of porosity on the wear behavior of YSZ abradable coating under simulated working conditions was studied using the high-temperature and ultra-high-speed abradability test rig. The results show that the porosity significantly influences the macroscopic morphology and abradability of the YSZ coating at the experimental temperatures of 1000 °C, with the blade tip velocity of 350 m/s, and the feed rate of 50 μm/s. The wear degree of the blade gradually decreases as porosity increases, and the incursion depth ratio (IDR) dramatically decreases. When the porosity reaches its maximum value, the wear scar of the coating is smoothest, and there is no discernible wear on the blade, the IDR value reaches its minimum, and the abradability of the coating reaches its maximum. Besides, brittle fracture in the YSZ coating with high porosity is concluded to be the reason for better abradability.